The relationship between inbreeding and melanoma status (graded from 0 to 4) and vitiligo depigmentation (grad­ed from 0 to 3) was analysed by regression model. The study includes 376 animals of both sexes at the age of 1-25 years. The evaluation of horses was performed repeatedly during 4 consecutive years. Melanoma and vitiligo were detected visually and by palpation. The average inbreeding coefficient (FX) calculated from 33 generations of ancestors reached 13 %. Individual inbreeding generally had a significantly negative impact on melanoma and vitiligo in back body parts and non-significant effect on vitiligo in head part. In general, inbreeding appears to be a factor that potentially influ­ences the expression of melanoma and vitiligo in Old Kladruber horses.