A rapid dot blot hybridization assay for the detection of B19 parvovirus DNA in human sera was developed. Small portions of four serum samples were mixed, filtered onto a nylon membrane, and hybridized with a digoxigenin-labeled DNA probe; for each membrane, 380 serum samples could be tested. When a dot was positive by the hybridization assay, the four serum samples dotted together were separately tested to identify the sample positive for B19 DNA. A total of 10,150 serum samples submitted for viral serological and laboratory investigation with no specific requests for B19 testing were analyzed. Nine serum samples were positive for B19 DNA by dot blot hybridization assay, and the results were confirmed by electron microscopy. This method has proven to be reliable, economical in terms of time and costs, and useful for large-scale screening of clinical specimens, both for diagnostic work and for a source of antigen.