Pyometra is a life-threatening uterine infection, accompanied by accumulation of intrauterine purulent exudate. The objective of this study was to show the recent laboratory and histopathological finding of pyometra in dogs with their correlation to their ages, and postoperative outcome. In this study, eleven cases of pyometra out of 115 female dogs of different ages and breeds were admitted to the Veterinary Teaching Hospital/College of Veterinary Medicine/University of Sulaimani from 2017 to 2021 for the purpose of ovariohysterectomy (OHE). They were diagnosed according to history, clinical signs, physical examination and the trans-abdominal ultrasound inspections. The uterine content and biopsy were collected during OHE for bacteriological and histopathological study respectively. The pyometra-uteri were plated on blood agars for 24 hours. The growing bacterial colonies were inoculated on Mannitol Salt, MacConkey and Eosin Methylene Blue (EMB) agar, and their strains were determined using the VITEK 2 system. In the results, a significant difference was found between the cases of pyometra and the normal bitches, the average age of the pyometra-dogs was 265 months old (±176.56 STD), while the average age of non-pyometra bitches was 23 months old (± 15.64 STD). Escherichia coli and Staphylococcus cohnni were recovered from the infected uterus. Chronic suppurative endometritis or metritis were identified, which associated with purulent and mucopurulent inflammatory exudates in the uterine lumen, focal epithelial sloughing, endometrial hyperplasia and fibrosis, cystic dilatation of the endometrial gland and infiltration of the endometrial stroma by mixed inflammatory reaction consisting of mononuclear and neutrophilic polymorphonuclear inflammatory cells. It was concluded that pyometra was an age-related infection and the periodic reproductive examination should be carried out for prompt surgical treatment.