Abstract: In 1979 a registry of large (20 cm or more in diameter) congenital nevocytic nevi was established at the NYU Medical Center. To date. 56 patients have been entered. Seven were lost to follow-up. An additional two patients had melanoma on entry into the study and were therefore excluded from the results of prospectively following such patients for the development of melanoma. Thus, this report concerns 47 individuals who were followed prospectively fora mean of 53 months, only 1 of whom developed melanoma. This was a 2-month-oId girl at entry into the study who subsequently developed Tou-raine's syndrome. She eventually developed a primary melanoma in the central nervous system and died of metastatic disease at the age of 21 months.