Uterine tumours in the bitch are considered rare. The most common are leiomyomas representing more than the 90% of all uterine canine tumours. Very few cases of uterine malignant tumours have been described in the veterinary literature and uterine liposarcoma had never discovered. Also in human medicine lipomatous tumours, whether benign or malignant, are very rare in the uterus. These tumours may arise from the misplacement of an embryonic progenitor cell, metaplasia of mature mesenchymal tissues of other types, perivascular adipocytes or from traumatic displacement of adipocytes. The authors describe a case of unilateral liposarcoma in the uterus of a German Shepherd dog and its radiographic, ultrasonographic evaluation and the histopathological appearance.