Using the data base for melanoma incidence compiled by the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute, we compared the incidence and anatomic distribution of primary cutaneous melanomas in Hispanic and non-Hispanic Caucasian populations and in blacks between 1973 and 1981. Cases were divided into United States whites, New Mexico (NM) whites (non-Hispanic Caucasians), NM Hispanics, Puerto Rico (PR) residents by definition Hispanic, and US blacks. Among whites, the highest incidence was 8.0 per 100,000 and was ten times that of US blacks. The incidence among PR and NM Hispanic residents was 1.6 to 3.7 times that of US blacks. The anatomic distribution among NM Hispanics was similar to US and NM whites for both genders. In contrast, among PR residents the anatomic distribution in both genders was most common for the leg, similar to that for blacks. Spaniards who migrated to PR have more admixture with blacks from Africa than Spaniards who migrated to the mainland. This suggests a genetic predilection for the occurrence of melanoma on the lower extremity among PR residents as opposed to NM Hispanics.