Patients with human immunodeficiency virus, those who are posttransplant, and those undergoing chemotherapy are populations who are immunocompromised and present to the emergency department with abdominal pain related to their disease processes, opportunistic infections, and complications of treatment. Emergency department practitioners must maintain vigilance, as the physical examination is often unreliable in these patients. Cross-sectional imaging and early treatment of symptoms with aggressive resuscitation is often required.