Abdominal masses are a common presentation in feline patients, and clinical signs commonly include weight loss, inappetence, vomiting and diarrhoea. The first step in investigation is to consider the likely differential diagnoses and obtain base line haematology and biochemistry to assess for red or white blood cell changes. Investigation of the mass should include abdominal ultrasound to confirm organ of origin, and needle aspirates or trucut biopsy. Ultrasound may give a good indication of the likelihood of successful resection and guide the decision to proceed with additional staging or surgery. The most common abdominal mass in cats is intestinal lymphoma, staging should include testing for FIV/FeLV, and thoracic radiographs if the budget permits. As lymphoma is a systemic disease, chemotherapy is indicated, regardless of staging and surgical intervention. In some patients, however, it is of benefit to excise the mass prior to chemotherapy, in the case of obstruction for example. Other intestinal tumours in felines include carcinoma, mast cell tumour and sarcoma. Abdominal masses may also arise from mesenteric lymph nodes and other organs such as liver, spleen pancreas, bladder or adrenal gland. This session uses a case-based approach to discuss differentials for and investigation of feline abdominal masses.