A four-year old bitch which showed occasional hemomorragic exudate from the vulva for two weeks after the previous estrus 7 months ago was ovariohysterectomied. About 200m1 of sanguineous fluid was flowed out from the uterus and some scattered blood clots were found in both uterine horns. Hematometra of the bitch which was presumed to occur during the proestrus two weeks ago was thought to progress into early pyometra at the time of diagnosis. To diagnose hematometra, vaginal examination using vaginal speculum or vaginoscope and hematological examination were performed. Radiography and ultrasonography were also proved to be of use to diagnose hematometra. Treatment for hematometra was considered to be the same as for the case of pyometra.