Anemia in HIV-infected patients is a common clinical manifestation. We report on a 31-year-old Thai male, who had been HIV positive for 6 years, did not harbor any opportunistic infection, and had been receiving Highly Active Anti Retroviral Therapy (HAART) for one month, and who developed severe anemia. Investigation revealed pure red cell aplasia, suspected secondary to parvovirus B19 infection. This diagnosis was confirmed by the detection of parvovirus B19 DNA in his serum. He received blood transfusions for supportive treatment and continued on HAART to improve his immune status and to resolve the anemia. This case suggests that parvovirus B19 infection should be considered as a possible cause of anemia in HIV-infected individuals.