Mammary tumors (CMT) in dogs in Iraq may be induced by carcinogenic war ordnance. In our study, 10 virgin un- spayed military/pet bitches aged 5-15 years presented with abnormal masses in the abdomen with painful oedema, swelling, anorexia, weight loss, weakness and mild fever. Examination of regional lymph nodes and thoracic radiography confirmed metastasis. Tumors were excised and determined to be mostly adenocarcinomas involving multiple glands, solid in texture, 5-15 cm in size, mostly in the inguinal mammary glands at stage T3: >5 cm. Microscopy confirmed presence of adenocarcinoma in 8 dogs and solid carcinoma in 2 with half of tumors being grade III. Tumors had pleomorphic hyperchromatic cell nuclei in stroma, epithelial cells of ducts with squamous metaplasia, fibrosis and infiltrates of inflammatory cells in interstitial mammary tissue. In papillary carcinomas, we also found papillary projections into glandular acini, with proliferation of epithelial cells. Gross lesions appeared as multiple ulcerated cranial abdominal masses with congestion and bloody edema. Expression of oestrogen (ER) and progesterone receptors (PR), and proliferation marker (Ki-67) were determined by immunohistochemistry. Samples were negative for ER and PR except for one PR sample which stained strongly. This dog had a small low grade tumour (3 cm) grade. Tumors from 7 dogs were strongly positive to Ki-67 localized in the nuclei of cells, but 3 tumors stained negative or weak. Follow up every 6 months for 18 months included health status, recurrence or metastasis. Only 3 dogs survived to 18 months, others died by 12 months.