This study included thirty stallions (4 to 12 years old) admitted to the Surgery clinic, Faculty of Veterinary Medicine, Cairo University for castration. A preliminary general examination in conjunction with visual inspection and manual palpation of both testicles were carried out for each animal. Fine needle aspiration cytology (FNAC) of the testis was performed in these animals and the cytological evaluation was recorded. After castration, testicular samples were collected from the same testis for histopathological investigation. Results of histopathological investigation were compared with those of fine ncedle aspiration cytology. The present study indicated that, FNAC is a non-invasive practical technique that can be used Satisfactorily for diagnosis of testicular affections and infertility in stallions.