Parvovirus B19, a non-enveloped single stranded DNA virus is distributed worldwide. Sero-prevalence in adult populations amounts to approximately 50%. Clinical manifestations vary depending on the Immune status of the infected individuals and may include mild childhood Infection as well as hydrops fetalis due to intrauterine infection. To determine the prevalence of this infection among the immunocompromized individuals in Thailand, we determined, by indirect ELISA, levels of IgM and IgG antibodies to the parvovirus B19 in 106 immunocompromized children. These included 49 children who were on chemotherapy for treatment of malignancies, 18 who were receiving immunosuppressive drugs after organ transplantations, 14 who were under a regimen of corticosteroids and 25 who were positive for antibodies to HIV. The average prevalence of IgG antibodies in 106 children was 16.0%; the prevalence of antibodies was 33.3% in post-transplanted group, 16% in children positive for HIV, 12.2% in the group receiving chemotherapy for malignancies and 7.6% in the group treated with corticosteroids. All children were negative for IgM antibodies to parvovirus B19.