In order to study the inheritance of melanocytic lesions in the Munich Miniature Swine (MMS) Troll, we established the F1-, F2- and R1-generations, starting with one melanoma-bearing MMS-Troll boar and four German Landrace sows as founder animals. A total of 168 animals were born, 24 in the F1-, 111 in the F2-, 19 in the B1DL-, and 14 in the B1Troll-generation. Benign lesions with lentigoid melanocytic hyperplasia or nests of hyperplastic melanocytes like in human junctional nevus were seen in 10 (41.7%) F1-, 17 (15.3%) F2-, 2 (10.5%) B1DL-, and 6 B1Troll-animals. Malignant melanomas occurred only in the F2-(4 animals; 3.6%) and in the B1Troll-(1 animal; 7.1%) generation. The observed segreation suggests different modes of inheritance for nevi and melanomas. The segregation of nevi can be explained by a major gene model with additional modification by a polygenic component. For melanoma, a major gene model does not fit the data sufficiently. Therefore, a two-or-three-locus model with doubled or tripled recessive affected animals has to be supposed for the inheritance of melanoma. Influence of SLA-haplotypes could not be observed.