In Lusaka, Zambia, rotavirus (RV) and human immunodeficiency virus (HIV) infection commonly coexist; 132 (25%) of 537 consecutively studied infants < 5 years old hospitalized with diarrhea were positive for both viral infections. Infants with RV infection were younger than those who were RV-negative (P > .05), and infants with both viruses more frequently experienced dehydration (P < .05). HIV-infected children more often exhibited respiratory symptoms on admission to the study (P < .0001) and were more frequently underweight (P < .0001) than were HIV-negative children, independent of RV infection. The mortality rate was highest in HIV-positive infants (P < .05), and coinfection with RV did not increase the risk of fatality. This study demonstrates that while RV and HIV infections commonly coexist in one region of Africa, RV infection is no more common nor is the illness more severe in HIV-positive infants.