There is still little data available about the epidemiology of childhood onychomycosis. Looking at our laboratory figures over a 10-year period provided us with some useful information. Nail keratin samples were taken by dermatologists from 21,557 patients with nail conditions, mainly in the Brussels region. The specimens were examined by direct microscopy and/or histology, and cultured on Sabouraud medium agar. Only patients less than 17 years of age were considered as children. Clinical information was gathered about age, sex, and the location of the infected nail. Nine hundred sixty-three of the samples were from children, and 296 of those children had proven onychomycosis. More than three-fourths of the cases were found in children more than 6 years old, and boys were more frequently affected than girls. Toenails were the predominant location of infection. Trichophyton rubrum was the main pathogen, followed by Candida spp. and Trichophyton interdigitale. One case was caused by Scopulariopsis spp. As in adults, onychomycosis is probably the main nail disease in children. After the age of 6 years, the presentation is very similar to that in adults: toenails are mostly involved, and T. rubrum, the main pathogen, is responsible for distal and lateral subungual onychomycosis.