Gastrointestinal illness (abdominal cramps, vomiting, and diarrhea) occurred suddenly among children and staff at two jointly owned, child day care centers in Fairfax, Virginia. Food histories were obtained for 80 persons. Illness was associated with eating chicken fried rice that had been served at a catered lunch on July 21. Bacillus cereus was isolated from leftover chicken fried rice and from vomitus from one child, but not from samples of leftover milk. Other food items served were not available for analysis. The rice had been cooked the night before and cooled at room temperature prior to refrigeration. Chicken was added in the morning when the rice was fried. The fried rice was served and held at the child care centers without refrigeration.