A total of 63 cases of cutaneous malignant melanoma in children have been reported to the Danish Cancer Registry during the 40-year period from 1943-1982. In order to describe the true incidence of childhood melanoma in Denmark, a clinical and pathological evaluation was performed. Not surprisingly we found that childhood melanomas were gravely overdiagnosed in Denmark. Nine cases of childhood melanoma were identified in our material. Seven of these were aged 10 to 14 years. Two of the tumours had developed in congenital giant naevi. The crude incidence rate was estimated to be between 0.24 x 10(-6) and 0.32 x 10(-6). In Denmark this corresponds to one new case of childhood melanoma every 3 to 4 years.