An epidemic of coxsackievirus B2 infections occured at a boys summer camp. The resulting illness was characterized by malaise, headache, muscle pain, and high fever that persisted for four to six days. The boy in the index case arrived at the camp the first day of the season. The attack rate was 89% among campers and 47% among counselors. The spread of infections appeared to be on a person-to-person basis and in a disorderly fashion. Unusual features of the epidemic included the high attack rate, restriction of infection to the camp residents, and evidence of prolonged pharyngeal viral shedding. Conditions at camps are ripe for similar epidemic and the potential problem is greater than is generally realized.