A thirteen-year-old, neutered, female Domestic Shorthair (DSH) was referred to the hospital with a suspicion of traumatic uroabdomen. Abdominal ultrasound revealed free peritoneal fluid and cellular infiltration of the urethra, kidneys, abdominal lymph nodes and cecal wall. Analysis of the free fluid confirmed the presence of uroabdomen. Cytology of the infiltrative lesions in the kidneys, urethra and lymph nodes confirmed the presence of multicentric malignant lymphoma. To the authors’ knowledge, this is the first case report of lymphomatous infiltration of the urethra in a cat.