Four hundred and eighty-five primary malignant skin tumours submitted for histological diagnosis in Iceland during the period 1955--1974 were typed according to the WHO histological classification. The incidence of these tumours, age-adjusted to the "World" population, was 12.6/100.000 in males and 11.0/100.000 in females. These are very low figures for a white population. The distribution by type among males was: basal cell carcinoma 66.8%, squamous cell carcinoma 22%, malignant melanoma 7.2% and others 4%. Among females: basal cell carcinoma 66.9%, malignant melanoma 20.8%, squamous cell carcinoma 10.2% and others 2.1%. The exposed areas of the body were affected much more frequently than other areas. The results support the theory that intensity of solar radiation is of major aetiological significance.