OBJECTIVE To establish a method of extracting DNA from the paraffin-embedded epidermal tissue and examine the amplification of beta-catenin gene by polymerase chain reaction (PCR) analysis. METHODS Exon 3 of the beta-catenin gene was amplified by PCR in 14 paraffin-embedded Bowen's disease (BD) of various weight and years. RESULTS The amplification of exon 3 of beta-catenin gene was successful in all the 10 mg and 20 mg samples, but not in the 5 mg samples. The amplification of exon 3 of beta-catenin gene was successful in 9 samples embedded within 10 years, and in only 2 of the 5 samples embedded more than 10 years. CONCLUSION Epidermal tissue whose weight is 10 mg or more within 10 years of embedding can be used in the amplification of purpose gene by PCR.