Over an 8-year period from 1973 through 1980, Corynebacterium hemolyticum was isolated from 103 of 24,695 throat cultures done at our hospital. Medical records were available for review from 33 of the 80 patients with a positive culture. Pharyngitis was present in all but 1, and 20 of the 32 symptomatic patients had a diffuse, erythematous, macular skin rash, often with a fine papular component, on the extremities and trunk. Screening of household contacts of 9 patients showed the presence of C. hemolyticum in the pharynges of 6 of 17 siblings but in 0 of 10 parents. Therapy with benzathine penicillin G or erythromycin resulted in rapid clinical improvement in most patients. In contrast to streptococcal pharyngitis, which is predominantly a disease of childhood, C. hemolyticum infection affects mostly teenagers and young adults: 30 of the 33 patients in this study were between the ages of 11 and 22. Within this age group, infection with C. hemolyticum is an important cause of pharyngitis associated with a scarlatiniform skin rash.