Edward Lawrie Tatum (December 14, 1909 - November 5, 1975) was an American geneticist. He shared half of the Nobel Prize in Physiology or Medicine in 1958 with George Wells Beadle for showing that genes control individual steps in metabolism. The other half of that year's award went to Joshua Lederberg.

Beadle and Tatum's key experiments involved exposing the bread mold Neurospora crassa to x-rays, causing mutations. In a series of experiments, they showed that these mutations caused changes in specific enzymes involved in metabolic pathways. These experiments, published in 1941, led them to propose a direct link between genes and enzymatic reactions, known as the "one gene, one enzyme" hypothesis.

Tatum went on to study genetics in bacteria. Tatum and his student Lederberg showed that the bacterium Escherichia coli could share genetic information through recombinant events.

Tatum was born in Boulder, Colorado. He attended college at the University of Chicago and received his PhD in biochemistry from the University of Wisconsin in 1934. Starting in 1937, he worked at Stanford University, where he began his collaboration with Beadle. He then moved to Yale University in 1945 where he mentored Lederberg. He returned to Stanford in 1948 and then joined the faculty of Rockefeller University in 1957. He died in New York City.