The Oldest Programming Languages Still in Production Use

Somewhere right now, a FORTRAN program written in the 1970s is predicting tomorrow’s weather. A COBOL system is processing your credit card transaction. A Lisp-based AI is helping plan a spacecraft’s trajectory. And the C code in your phone’s operating system traces its lineage to 1972.

In an industry obsessed with the newest frameworks and trendiest languages, it’s easy to forget that some of the oldest code in existence still powers critical infrastructure. These aren’t museum pieces—they’re the backbone of modern civilization.

Here are six programming languages, all over 40 years old, that refuse to retire.

1. FORTRAN (1957) — 68 Years Old

The language that proved high-level programming could work.

When John Backus and his team at IBM released FORTRAN in 1957, skeptics said no automatic system could produce code as efficient as hand-written assembly. They were wrong. FORTRAN’s compiler generated code that matched human optimization, and suddenly scientists could write programs using mathematical notation instead of cryptic machine instructions.

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program weather_model
    implicit none
    real :: temperature(1000, 1000, 100)
    ! Process atmospheric data...
end program weather_model

Where It’s Still Running

  • Weather Forecasting: The Global Forecast System (GFS) and European Centre for Medium-Range Weather Forecasts (ECMWF) run on millions of lines of FORTRAN. When you check tomorrow’s forecast, thank FORTRAN.

  • Climate Science: IPCC climate models that inform global policy decisions are built on 40+ years of optimized FORTRAN code.

  • Nuclear Physics: Simulations at CERN and national laboratories use FORTRAN libraries refined over decades.

  • Computational Fluid Dynamics: NASA and aerospace companies design aircraft and rockets using FORTRAN simulations.

Why It Won’t Die

FORTRAN isn’t just legacy code that’s too expensive to replace. Modern FORTRAN (the 2023 standard dropped the all-caps) includes object-oriented programming, parallel processing with coarrays, and performance that still beats most alternatives for numerical computation.

When your career depends on predicting a hurricane’s path or simulating nuclear reactions, you use the tool with 68 years of proven reliability.

Surprising fact: More scientific papers cite FORTRAN code than any language except Python—and Python often calls FORTRAN libraries under the hood.

Learn FORTRAN →

2. Lisp (1958) — 67 Years Old

The language that taught computers to think.

John McCarthy created Lisp at MIT as a practical notation for artificial intelligence research. It introduced concepts that wouldn’t appear in mainstream languages for decades: garbage collection, dynamic typing, recursion, and the revolutionary idea that code and data could be interchangeable.

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;; Lisp's syntax hasn't changed in 67 years
(defun factorial (n)
  (if (<= n 1)
      1
      (* n (factorial (- n 1)))))

Where It’s Still Running

  • NASA’s Jet Propulsion Laboratory: The Deep Space 1 mission used Common Lisp for its autonomous control system—a program that could diagnose problems and make decisions millions of miles from Earth.

  • Google Flights: ITA Software built QPX, the flight search engine powering Google Flights, Kayak, and Orbitz, in Common Lisp. It was so good that Google acquired the company.

  • Grammarly: The core NLP engine that checks your writing was originally built in Common Lisp.

  • Financial Trading: High-frequency trading firms use Lisp derivatives for their flexibility and rapid development cycles.

Why It Won’t Die

Lisp’s macro system allows programmers to extend the language itself—a capability most modern languages still can’t match. The Common Lisp ANSI standard from 1994 remains unchanged, meaning code written 30 years ago runs without modification on modern systems.

Surprising fact: Emacs, one of the most powerful text editors, is essentially a Lisp interpreter with a text editing mode. Programmers have been customizing it with Lisp code since 1976.

Learn Common Lisp →

3. COBOL (1959) — 66 Years Old

The language that moves your money.

Grace Hopper and the CODASYL committee designed COBOL to be readable by business managers, not just programmers. Its verbose, English-like syntax was revolutionary—and sometimes mocked—but that verbosity became a feature: COBOL code often serves as its own documentation.

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IDENTIFICATION DIVISION.
PROGRAM-ID. BANK-TRANSACTION.

PROCEDURE DIVISION.
    IF BALANCE IS GREATER THAN WITHDRAWAL-AMOUNT
        SUBTRACT WITHDRAWAL-AMOUNT FROM BALANCE
        DISPLAY "Transaction approved"
    ELSE
        DISPLAY "Insufficient funds"
    END-IF.
    STOP RUN.

Where It’s Still Running

The statistics are staggering:

  • 95% of ATM transactions run through COBOL systems
  • 80% of in-person financial transactions touch COBOL code
  • $3 trillion in daily commerce is processed by COBOL
  • 220 billion lines of COBOL remain in production worldwide

The Social Security Administration, major banks, insurance companies, and airlines all depend on COBOL systems that have been running—and being carefully maintained—for decades.

Why It Won’t Die

Rewriting these systems isn’t just expensive (often hundreds of millions of dollars)—it’s dangerous. Decades of accumulated business rules are embedded in that code. Every edge case, every regulatory requirement, every hard-won bug fix represents institutional knowledge that’s nearly impossible to recreate.

The Y2K crisis proved both COBOL’s dominance and its staying power. Companies spent an estimated $300 billion fixing date handling in COBOL systems—then kept running them.

Surprising fact: During the 2020 pandemic, states scrambled to find COBOL programmers to handle surging unemployment claims. New Jersey’s governor publicly appealed for volunteers who knew the language.

Learn COBOL →

4. BASIC (1964) — 61 Years Old

The language that made programming accessible.

John Kemeny and Thomas Kurtz at Dartmouth College had a radical idea: everyone should be able to program computers, not just scientists and engineers. BASIC (Beginner’s All-purpose Symbolic Instruction Code) was designed to be learned in hours, not semesters.

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10 PRINT "Hello, World!"
20 INPUT "What is your name"; N$
30 PRINT "Nice to meet you, "; N$
40 END

The Original BASIC Legacy

The original BASIC itself is largely a historical artifact—you won’t find line-numbered BASIC running production systems today. But BASIC’s influence transformed the industry:

  • Microsoft’s origin story: Bill Gates and Paul Allen’s first product was Altair BASIC in 1975. Every Microsoft product traces back to BASIC.

  • The home computer revolution: Apple II, Commodore 64, TRS-80, and countless other early PCs shipped with BASIC built in. An entire generation learned to program by typing BASIC listings from magazines.

  • The democratization of programming: Before BASIC, programming required expensive equipment and formal training. BASIC proved that ordinary people could write useful software.

Where Its Descendants Still Run

While classic BASIC faded, Visual Basic became one of the most successful programming languages in history:

  • Excel and Office macros: VBA (Visual Basic for Applications) powers automation in millions of spreadsheets and documents worldwide
  • Enterprise applications: Legacy Visual Basic 6 applications still run in banks, hospitals, and government agencies
  • VB.NET: Microsoft’s modernized Visual Basic continues as a first-class .NET language

Surprising fact: A 2020 survey found VBA among the top 10 most-used programming languages, largely because of its integration with Microsoft Office. The language that taught millions to program in the 1980s is still teaching (and being used) today.

Learn BASIC →

5. C (1972) — 53 Years Old

The language that built the modern world.

Dennis Ritchie created C at Bell Labs to rewrite the Unix operating system. It was a perfect middle ground: close enough to the hardware for systems programming, abstract enough to be portable across different machines. That combination proved irresistible.

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#include <stdio.h>

int main() {
    printf("Hello, World!\n");
    return 0;
}

Where It’s Still Running

The question isn’t where C is running—it’s where it isn’t:

  • Every operating system: Linux, Windows, macOS, iOS, Android—all have kernels written substantially or entirely in C
  • Every database: PostgreSQL, MySQL, SQLite, Oracle—C at the core
  • Every browser: The rendering engines are C and C++
  • Every embedded system: Your car, refrigerator, pacemaker, and thermostat likely run C
  • Most language runtimes: Python (CPython), Ruby (MRI), PHP—all implemented in C

C isn’t just a language that’s still used—it’s the foundation everything else is built on.

Why It Won’t Die

C’s minimalism is its superpower. The entire language specification fits in a few hundred pages. A C compiler can target any processor ever made. C code written in 1985 often compiles unchanged today.

When you need maximum performance, direct hardware access, or code that will run for decades on systems that don’t exist yet, C remains the obvious choice.

Surprising fact: Git, the version control system that powers nearly all modern software development, is written in C. Linus Torvalds chose C for the same reasons he chose it for Linux: performance, portability, and simplicity.

Learn C →

6. Ada (1980) — 45 Years Old

The language where bugs aren’t an option.

The U.S. Department of Defense was drowning in programming languages—over 450 different ones across various projects. They held an international competition to design one language for all embedded systems. The winner, named after computing pioneer Ada Lovelace, was designed from the ground up for reliability.

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procedure Safe_Withdraw (Amount : Money) is
begin
   if Amount > Balance then
      raise Insufficient_Funds;
   end if;
   Balance := Balance - Amount;
end Safe_Withdraw;

Where It’s Still Running

Ada dominates industries where software failure costs lives:

  • Boeing 777 and 787: Primary flight control systems
  • Airbus A380: Avionics and flight management
  • Paris Metro Line 14: Fully automated driverless trains
  • Air traffic control: FAA and international systems
  • Ariane rockets: Launch vehicle control
  • Military systems: From missile guidance to command-and-control

Why It Won’t Die

Ada catches bugs at compile time that other languages catch in production—or never catch at all. Its strong typing prevents entire categories of errors:

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type Meters is new Float;
type Feet is new Float;

Distance_M : Meters := 100.0;
Distance_F : Feet := 328.0;

-- This won't compile: can't accidentally mix units
Total := Distance_M + Distance_F;  -- Compiler error!

Remember the Mars Climate Orbiter? It crashed because one team used metric units and another used imperial. That bug would have been caught at compile time in Ada.

Surprising fact: The SPARK subset of Ada can mathematically prove the absence of runtime errors. Systems like the UK’s air traffic control have been formally verified to never crash, overflow, or access invalid memory.

Learn Ada →

Why Ancient Languages Survive

These languages share common traits that explain their longevity:

1. Mission-Critical Reliability

When failure means crashed planes, lost billions, or incorrect nuclear simulations, organizations choose proven tools over trendy ones. A language that’s worked for 50 years is a better bet than one that’s worked for 5.

2. Accumulated Investment

The real cost of software isn’t writing it—it’s maintaining it. Billions of lines of code, decades of bug fixes, and generations of institutional knowledge can’t be easily replaced.

3. Continued Evolution

These aren’t frozen relics. FORTRAN 2023, COBOL 2023, and Ada 2022 are modern languages with modern features. They’ve adopted good ideas while maintaining backward compatibility.

4. Performance Where It Matters

For numerical computing (FORTRAN), financial transactions (COBOL), or systems programming (C), these languages still outperform or match modern alternatives in their domains.

What This Means for You

Even if you never write a line of COBOL or FORTRAN, understanding these languages matters:

  1. Career opportunities: Organizations desperately need developers who can maintain legacy systems. COBOL programmers command premium salaries.

  2. Perspective: Modern language features didn’t appear from nowhere. Garbage collection? Thank Lisp (1958). Structured programming? Thank ALGOL and its descendants. Understanding history helps you use modern tools better.

  3. Humility: Today’s hot framework might be tomorrow’s legacy system. The languages that survive prioritize stability, backward compatibility, and solving real problems over chasing trends.

Try Them Yourself

Every language in this article is documented on CodeArchaeology with Docker-based examples you can run immediately:

  • FORTRAN — Scientific computing foundation
  • Common Lisp — AI and symbolic computing
  • COBOL — Business data processing
  • BASIC — Accessible programming
  • C — Systems programming bedrock
  • Ada — Safety-critical systems

Or explore our encyclopedia of 1,200+ programming languages to discover the full breadth of computing history.

What’s the oldest code you’ve encountered in production? Share your archaeology stories on GitHub.

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