During a 15-day period in September and October 1969, an outbreak of infectious hepatitis affected the members of a college football team. Of 97 persons exposed, 90 were infected, 32 experienced typical icteric disease, 22 were anicteric but symptomatic, and 36 asymptomatic players were recognized as having significantly elevated serum glutamic pyruvic transaminase values (> 100 units). Other athletes, using the same facilities but arriving six days after the established date of exposure, were unaffected. The decision to obtain blood samples from the entire team, as soon as the initial cases were recognized, resulted in the demonstration of an unexpectedly high attack rate of 93%. Epidemiologic investigation revealed that an infected group of children in the neighborhood, an imperfect drinking water supply, a warm August day, a football team in training, and a local fire were links in the chain which resulted in this most unusual outbreak of infectious hepatitis.