An outbreak of Cryptosporidium parvum, genotype 1, occurred on a Washington, D.C., college campus. A case-control study indicated that eating in 1 of 2 cafeterias was associated with illness. Eating dinner on September 22 was associated with a risk of illness. Several food workers reported having gastroenteritis. One of the ill food workers had prepared raw produce between September 20 and 22 while ill.