A female Russian blue cat has invited Animal Hospital because of diarrhea after the mating. The eggs on internal parasite and Giardia sp. were diagnosed in the feces floating test, and treated with metronidazole, pyrantel pamoate and antibiotics. There were no diarrheal sign in the reevaluation, but anorexia, polydipsia, polyuria, and vaginal discharge was newly induced. Streptococcus sp. was inspected by smearing of vaginal discharge, and enlarge-ment of uterus was evaluated by x-ray examination. This case was confirmed as pyometra and recovered by ovariohysterectomy on the basis of that examination. The rate of incidence in feline pyometra is not so high as in the canine.