The aim of this study was to determine whether the canine endometrium could be examined by hysteroscopy. Eight German shepherd bitches were used. Two bitches were in dioestrus, five were in anoestrus and one was about 8 weeks post partum. The uterus was exposed through a ventral celiotomy. A 3 mm straight laparoscope or a 4 mm laparoscope with a 30 degrees angle, and a catheter for inflation of the uterus were used. After hysteroscopy the bitches were spayed and the uterus of each bitch was examined macroscopically and histologically. Endometrium and uterotubal junctions were visible in all bitches. The cervix and caudal uterine body could not be visualized in three bitches as two bitches had uterine discharge and air escaped through the cervix in the other bitch. In the post-partum bitch, dark-brown sites of implantation were observed. Four bitches (aged 9, 22, 25 and 31 months) had endometrial cysts (0.5-2.0 mm in diameter). Hysteroscopy caused petechiae and ecchymosis in the endometrium of four bitches. Traumatization of the endometrium affected only the epithelium and the most superficial part of the lamina propria. In conclusion, hysteroscopy appears to be a very sensitive tool for evaluation of the canine endometrium. Further research is necessary to determine the effects of hysteroscopy on subsequent fertility.