We report a 6-year-old boy who developed depigmentation within a congenital melanocytic nevus at the age of 3 years. During the following months a halo phenomenon and vitiligo-like lesions distant from the nevus appeared. A thorough search for malignant melanoma was negative. A second patient, a 45-year-old woman, had a large congenital nevus on the trunk with marked satellitosis. At the age of 20 years, partial regression of the large nevus occurred and, in addition, halos developed around almost all smaller nevi. Repeated searches for associated malignant melanoma were negative. We review the rare cases of halo congenital nevi and emphasize that depigmentation is not necessarily associated with malignant degeneration.