Background. The gastrointestinal (GI) tract is important in the pathogenesis of human immunodeficiency virus (HIV) infection. We report a case series of lower GI endoscopic and histopathologic findings of HIV-infected individuals after presentation with acute infection. Methods. We performed a retrospective case review of individuals infected with HIV who enrolled between August 2010 and April 2013 in a primary infection treatment trial. All participants started the trial during acute infection and underwent colonoscopy with biopsies at baseline and after the start of antiretroviral treatment. Results. Twenty acutely infected individuals were included in the study (mean age, 33 years; range, 20-54 years). All participants were male who reported having receptive anal sex as an HIV risk factor. Nine individuals (45%) had at least 1 finding by colorectal pathology; 1 person had 2 diagnoses (diverticulosis and focal active proctitis). The histopathological findings revealed anal dysplasia in 3 cases: 2 had high-grade anal intraepithelial neoplasia (AIN) and 1 had low-grade AIN. Two persons had a colorectal polyp, 1 hyperplastic and 1 adenomatous. Three persons were diagnosed with diverticulosis, and 2 persons were diagnosed with proctitis, including 1 with focal active proctitis and 1 with cytomegalovirus proctitis. Conclusions. To our knowledge, this is the first case series report of lower GI disorders in acute HIV-infected individuals. Although the causal relationship remains uncertain, we describe the endoscopic findings that were observed during acute HIV infection among men who have sex with men. Understanding the prevalence of these pathologies may likely shed light on how acute HIV infection damages the lower GI tract.