A 66-year-old man with no past medical history presented with 2 weeks of fever, abdominal pain and watery diarrhoea. He tested positive for human immunodeficiency virus (HIV), and the CD4 + T-cell count was 43.8/mL. Endoscopy revealed multiple circumferential ulcers in the ascending colon (Figure 1), transverse colon and caecum. Biopsies from the colonic ulcers showed numerous amoebic trophozoites (Figure 2, arrows) and eosinophilic intranuclear inclusion bodies (Figure 2, arrowheads). Immunohistochemistry for cytomegalovirus (CMV) (Dako mouse anti-CMV monoclonal antibody clone CCH2 + DDG9) was positive in the eosinophilic intranuclear bodies (Figure 3). Polymerase chain reaction tests were positive for Entamoeba histolytica in stool, and for CMV in colon tissue.Compared with CMV colitis, invasive amoebic colitis is rare, and was detected in only 1.3% of patients with HIV with CD4 + T cell counts <50/mL (Blanshard et al., 1996). Recent studies from Japan have shown the seropositivity rate for E. histolytica to be low among volunteers (2.64%), but much higher among patients with HIV (28.3%) (Yanagawa et al., 2016(Yanagawa et al., , 2020. As gastroenteritis in patients with HIV typically results from multiple pathogens,