An explosive epidemic of pharyngitis due to Group A streptococci occurred among the cadets at the United States Air Force Academy during a seven-day period in the spring of 1968. Symptoms of streptococcal pharyngitis developed in over 1000 cadets during the course of the epidemic. Prompt institution of control measures probably confined the outbreak to the cadet wing and prevented extensive secondary spread. The epidemic strain was identified as a Group A, T-Type 12 streptococcus that could not be M-typed with available typing serums and may represent a new M-Type. An epidemiologic investigation incriminated a single food item as the vehicle of transmission. Nonsuppurative sequelae were not detected despite intensive surveillance.