Nirenberg, Marshall Warren (1927-), an American biochemist, shared the 1968 Nobel Prize in physiology or medicine for his role in deciphering the genetic code. He shared the prize with Robert William Holley and Har Gobind Khorana.

A native New Yorker, as a teen-ager Nirenberg developed rheumatic fever, prompting the family to move to subtropical Orlando, Florida. There he began taking notes on the flora and fauna he observed. Having earned his undergraduate degree in zoology and chemistry (1948) and his master's degree in zoology (1952) at the University of Florida in Gainesville, he completed a doctorate in biological chemistry (1957) at the University of Michigan in Ann Arbor. After a postdoctoral fellowship at the National Institutes of Health (NIH) in Bethesda, Maryland, he joined the staff as a research scientist. There he developed the procedure for deciphering the genetic code in living cells. He demonstrated that in protein production, each sequence of three chemical units—known as triplets or codons—in genetic material forms the arrangement for a specific amino acid. In 1961, he announced his discovery of the code for one amino acid. By 1966. Nirenberg had deciphered the code for the 20 amino acids involved in protein production.

In 1966, Nirenberg became senior research biochemist and chief of the laboratory of biochemical genetics at NIH's National Heart, Lung, and Blood Institute. Awarded the National Medal of Science by President Lyndon B. Johnson in 1965, in that year his research shifted toward neurobiology and neurogenetics. His recent work has included using advanced digital scanning technology to study the genetic development of neural networks in the brains of fruit fly embryos.

As a scientific statesman, Nirenberg has spoken out on behalf of endangered foreign scientists, criticized U.S. government cuts in biomedical research programs, endorsed the “World Scientists' Warning to Humanity” on threats to society and the earth's environment, and supported the ban on human cloning.