This article reports an unusual presentation of pyometra in a pet rabbit. A 2-year-old mixed-breed female rabbit with pelvic limb paralysis was referred for abdominal distension associated with prolonged depression and decreased appetite. Clinical examination and diagnostic imaging (radiographs and ultrasound) led to the provisional diagnosis of pyometra, that was caused by the presence of an enlarged organ containing fluid material and occupying most of the caudal abdomen. Exploratory laparotomy was performed under general anesthesia. After abdominal wall incision along the linea alba, the uterus was immediately evident and the uterine wall was over-distended and damaged, with purulent material free in the abdominal cavity. Ovariohysterectomy was performed and uterine wall samples were sent for microbiological examination and antimicrobial susceptibility testing. The agent causing the pyometra was found to be Pseudomonas aeruginosa, which was resistant to enrofloxacin and ceftazidime. This is the first report of pyometra caused by P. aeruginosa in a pet rabbit, based on a literature search. Furthermore, a peculiarity of the present case is the occurrence of pyometra in a rabbit with no history of mating or parturition.Copyright © 2020. Published by Elsevier Inc.