Four cases of human parvovirus infection in which the main clinical manifestation was a polyarthritis are described. Four females with ages ranging from 30 to 32 years presented with acute symmetrical polyarthralgias involving hands and knees. In addition, evidence of synovitis in the ankles and tenosynovitis of the fingers was found in two and three cases respectively. Half of the patients noticed an erythematous rash in the preceding days. Laboratory studies were normal in all cases. Antinuclear antibodies and rheumatoid factor were not detected in any case. All patients had significant levels of IgG and IgM antibodies to parvovirus B19 at the time of presentation and a rise in IgG and a fall in IgM levels were seen at two months. All cases cleared up within two weeks without treatment.