We propose an one-step DNA extraction method suitable for the polymerase chain reaction. This procedure utilizes Chelex 100, a chelating in exchange resin. This technique was compared with a traditional technique (proteinase K lysis, phenol-chloroform extraction and ethanol precipitation) for isolation of human cytomegalovirus DNA from clinical samples. The procedure using Chelex 100 appeared to be a simple and fast extraction method for human cytomegalovirus DNA.