This study was aimed to investigate the expression of beta-catenin in leukemic cell lines and its relationship with pathogenesis of leukemia, semi-quantitative RT-PCR and Western blot were performed to detect the expression of beta-catenin in a panel of 15 human hematopoietic cell lines (U937, KG1a, Jurkat, K562, Namalwa, HEL, HUT78, Raji, Daudi, CEM, LCL-H, HL-60, NB4, J6-1, Ramos). Immunocytochemistry was performed in some of these cell lines to detect the location of beta-catenin. The results showed that the beta-catenin gene was widely expressed in most leukemic cell lines in various degree, the high expression of beta-catenin was found is U937, KG1a, Jurkat, K562 and Namalwa cells, middle expression of beta-catenin was observed in HEL, HUT78, Raji, Daudi and CEM cells, lower expression of beta-catenin was observed in LCL-H, HL-60, NB4, J6-1 and Ramos cells. The expression level of beta-catenin protein was identical to the expression level of beta-catenin mRNA. The expression of beta-catenin could be found in nuclei of all cells mentioned above, but their levels were different between them. Abundant beta-catenin also could be observed in nuclei of some leukemic cells by immunocytochemistry. It is concluded that overexpression of beta-catenin in leukemia cells, as a key mediator of Wnt signaling transduction pathway, indicates that the Wnt signaling transduction pathway may be aberrantly activated in leukemia.