Feline inflammatory bowel disease is a diagnosis of exclusion and a common cause of chronic gastrointestinal signs suhc as weight loss, variation in appetite, vomiting, diarrhea, and lethargy. Patients with intestinal small cell lymphosarcoma can present identical clinical signs, and differentiating between these two conditions can be a challenge. A companion article discusses the value of performing immunohistochemistry and polymerase chain reaction testing on intestinal biopsy samples for this purpose.