Reports to the Center for Disease Control on isolation of non-polio enteroviruses for the years 1971--1975 were analysed. During the 5 year period, enterovirus isolations were reported from 7 075 individuals. 90% of these occurred in the 7 month interval of May--November. Enteroviruses were isolated more frequently from males than females for all age groups in all 5 years. The incidence of reported isolations decreased with increasing age, and an inverse relationship between severity of disease and age was suggested. Clinical diagnoses associated with enteroviral isolations included aseptic meningitis, encephalitis, upper respiratory tract disease, non-specific febrile illness, gastroenteritis, pneumonia and lower respiratory tract disease, exanthem, and enanthem.