In order to distinguish follicular lymphoma (FL) from follicular hyperplasia (FH), immunohistochemical staining method was used to detect the expression of bcl-2 oncogene protein in 22 cases of FL and 14 cases of FH. The results showed that bcl-2 was positive in 19 and negative in 3 of the 22 FLs, but negative in 12 and weakly positive in 2 of the FHs. These findings suggest that bcl-2 can play an important role in the differential diagnosis of FL and FH.