Disseminated Mycobacterium avium complex (MAC) infection is an important AIDS-defining opportunistic infection. The introduction of antimicrobial prophylaxis and antiretroviral therapy (ART) markedly reduced the incidence of disseminated MAC infection and improved the survival of affected individuals. However, it seems that patients with new or recurrent MAC infection are still encountered in clinical practice. Our images captured the characteristic endoscopic findings of MAC duodenitis. The gastrointestinal (GI) tract appears to be a common port of entry for MAC infection in patients with AIDS. Early recognition of GI MAC infection by endoscopy in HIV-infected patients and initiation of anti-MAC therapy and ART may reduce morbidity and mortality.