Gastrointestinal (GI) lymphoma should be suspected in animals with an acute or prolonged history of signs of disease related to the GI tract. Systemic staging tests (complete blood count/chemistry/urinalysis/thyroxin levels/thoracic radiographs) are used to identify concurrent disease. Abdominal ultrasonography is useful to document intestinal wall thickening, mass lesions, concurrent organ involvement, lymphadenopathy, and abdominal lymphadenopathy. Ultrasound findings can be used to decide if the next diagnostic test should be laparotomy, laparoscopy, or endoscopy, with the goal of obtaining diagnostic histologic specimens. Histopathologically, lymphoma may be lymphoblastic or lymphocytic. Chemotherapy, including steroids and nutritional support, are essential in the management of alimentary lymphoma.