The authors examined the inheritance of the vertebral stripe in the progeny of F1,F2 and F3 generations of Rana rridibunda from Turkey. The female as unstriped and the male as striped. All F1, froglets were striped, in F2 froglets this colour pattern segregated according to MENDEL'S law 3:1 (95 frogs were striped and 29 unstriped). In F3 froglets which were received from unstriped parents, only unstriped individuals appeared. Numbers of females and males among individuals of both colour patterns were normal (1:1). The authors concluded that the vertebral stripe in R. ridibunda is controlled by an autosomic gene and that the allele responsible for the presence oflight stripe is dominant and its antagonistic one is recessive.