We report a simple and rapid method for direct DNA amplification of washed blood cells by PCR. Small samples (2-100 microliters) of blood were washed, the cells resuspended in a buffer and used directly for PCR after boiling. Amplification of a specific DNA sequence of the human transthyretin gene, directed by the primers, was successfully performed. The method gives comparable results to amplifications made by purified DNA from blood.