Seventeen cases of Sertoli cell tumor in dogs were found by searching medical records from 1971 to 1985. The average age of affected dogs was ten years, and most animals were of mixed breed. Most of the dogs were presented for reasons unrelated to the Sertoli cell tumor, however, most dogs had one or more clinical signs associated with Sertoli cell tumor. These signs included prostatic changes, alopecia and hyperpigmentation, bone marrow suppression, gynecomastia, and behavioral changes. The association of Sertoli cell tumor with cryptorchidism was obvious in these records, as ten of the dogs had one or both testicles undescended. Histopathological features of the tumors were variable and had no consistent correlation with metastatic potential. Some interesting comparisons can be made regarding these tumors in other domestic animals and in man.