This study was conducted under a working hypothesis that the repeating of selective breeding of normal rats with a slight impairment of glucose tolerance would produce spontaneous diabetes rats. This is the second report, 18 rats were selected by an oral glucose tolerance test from 211 normal Wistar rats obtained from an experimental animal farm. By the breeding 162 F1 rats were obtained. By the selective breeding in this way, 204 F2, 174 F3 and 215 F4 rats were obtained. The mean glucose tolerance curve became more diabetic with the increasing number of generations. The percentage of cases of a positive test for urine sugar during the glucose tolerance test increases with the number of generation. The results indicate the possibility of production of spontaneous diabetes from normal rats by the repetition of the selective breeding.