Vascular endothelial growth factor (VEGF) is one of the main angiogenic cytokines and plays an important role in the development of human solid tumors. However, it is not clarified whether VEGF governs the progress of the chronic myelogenous leukemia (CML). This study is to estimate VEGF expression in the bone marrow cells from normal and adult CML patients and various leukemic cell lines. Reverse transcription-polymerase chain reaction (RT-PCR) was used for detection of VEGF mRNA. VEGF concentrations in the cell cultural supernatant and the plasma from normal and CML patient bone marrows were determined by enzyme linked immunosorbent assay (ELISA). VEGF mRNA was positive in 67 of 72 cases of bcr/abl(+) CML patient bone marrow cells (93.1%), in 5 of 10 CML patients post Allo-BMT bone marrow cells (50%), and in 6 of 10 normal bone marrow cells (60%), the expression rate of VEGF mRNA in CML patients bone marrow cells was higher than that in CML patients post Allo-BMT and normal bone marrow cells. VEGF mRNA also expressed in the HL-60, K562, CEM, KG1a, NB4, and Nalm6 cells, but not in the Jurkat cells. The mean VEGF concentration in the plasma (380.6 pg/ml) from 22 untreated CML patients was 9 folds higher than that from 9 CML patients post Allo-BMT (38.0 pg/ml). The mean VEGF concentration in the cultural supernatant (499.8 pg/ml) of 17 newly diagnosed CML bone marrows was 2.5-folds higher than that in 11 normal donors (141.3 pg/ml). The CML marrow cells secrete more VEGF than normal marrow cells do. Our results suggest that the abnormality of VEGF transcription and translation expression may play an important role in the development of CML.