Human parvovirus B19 has been associated with several diseases. Aplastic crisis in patients with chronic hemolytic anemia, erythema infec-tiosum, hydrops fetalis and arthritis are among the common diseases caused by this virus infection. In the period between July, 1991, and March, 1992,48 patients with aplastic crises were hospitalized at Saudi Aramco-Dhahran Health Center, Dhahran, Saudi Arabia. Forty-six patients had homozygous sickle cell disease, one had hemoglobin H disease and one had hereditary elliptocytosis. Evidence of recent human parvovirus infection was present in 91% of the cases. Leukopenia was present in 21%, neutropenia in 27% and thrombocytopenia in 42%. This differs from previous reports in which red blood cell aplasia causing anemia was the only hema-tologic finding reported in most patients. There were no cases of erythema infectiosum in either the patients or the community during the epidemic and the reason for this phenomenon is not obvious. The almost limited occurrence of aplastic crisis in patients with sickle cell disease in a population with a high incidence of other types of chronic hemolytic anemias is of interest.