Six-hundred and fifteen young healthy Italian males were examined for the number, localization and clinical features of melanocytic naevi. The data were correlated with the phenotype and skin type of the subjects. Eighty-eight per cent had melanocytic naevi, 7% congenital naevi and 21.3% atypical naevi with a diameter greater than 5 mm and indistinct or irregular borders and were variable in colour. Of the sample only 2.43% had more than 30 naevi. Those subjects with blond or red hair, fair skin, blue or green eyes and with a skin type of I and II had higher numbers of naevi which were more often atypical than those subjects with dark hair, brown eyes and who were skin types III-V.