In this study, specimens from 59 cases of non-Hodgkin's lymphoma (NHL) were immunophenotyped with L26 and UCHL-I McAb, then investigated for gene rearrangement by PCR technique. The results showed that the rates of positive amplification of clonal IgH and TCR beta gene rearrangement were 71.4% (10/14) and 83.3% (10/12) respectively in the fresh tissues, and the IgH (semi-nested PCR technique) and TCR beta were 80% (12/15) and 73.3% (11/15) respectively in paraffin embedded tissues. Definitive diagnosis was made for the 6 cases which could not be diagnosed by routine and immunohistochemical methods, and all 6 exhibited IgH or TCR beta single band. No cases with pseudopositive amplification were discovered. This study suggested that the PCR technique was the most specific, sensitive and rapid detection method for clonal gene rearrangement in NHL.