The clinical features of 100 dysplastic nevi were tabulated. Although certain characteristics were present in most or all of these melanocytic nevi, there was a marked heterogeneity of other clinical features. The preponderant type of large (greater than or equal to 8 mm) melanocytic nevus in patients with classic dysplastic nevi is a papule or plaque with the following characteristics: multicoloration (various shades of tans, browns, reds, or black); slightly raised height for its broad diameter; mamillated surface; and lack of hypertrichosis. An atlas illustrates some of the clinical varieties of melanocytic nevi in this syndrome.