The incidence of malignant melanoma is increasing faster than that of any other cancer. It is important to identify subsets of the population at high risk of its development so that they can be observed more closely to identify early melanomas when they are curable. It has been reported worldwide that persons with the atypical mole (dysplastic nevus) syndrome are such a subset at increased risk. A risk gradient for the development of melanoma exists and varies from persons with one or two atypical moles and no family history of melanoma at one end of the spectrum to persons with the familial atypical multiple-mole melanoma syndrome at the other. Guidelines for the management of atypical mole syndrome are presented.