We analyzed data on molluscum contagiosum infection in the United States from two sources: the National Disease and Therapeutic Index Survey of private patients, collected during 1966-1983; and two sexually transmitted disease clinics, collected during 1977-1981. Patient visits to private physicians for molluscum contagiosum increased 11-fold from 1966 to 1983. Over the same time span, the proportion of private patient visits also increased: from 1.2 to 11.0 per 100,000 total clinic visits. Clinic patients, however, showed stable trends in proportions of individuals infected over the period 1977-1981. Clinic patients 15-24 years old and private patients aged 20-29 years were more likely to present with molluscum contagiosum than patients in other age categories. Like the prevalence of other viral sexually transmitted diseases in the private medical community, that of molluscum contagiosum infections appears to have increased dramatically over the 18-year span covered by this study.