Objective：To compare the transfection efficiencies among adenovirus，lentivirus and Lipofectamine 2000 and to explore an efficient way for U937 cells transfection. Methods：U937 cells were transfected with Lipofectamine 2000-plasmid（pGPHI/GFP/Neo），adenovirus vector（Adv-GFP-NC） and lentivirus vector（LV-GFP-NC），respectively. Expressions of green fluorescence protein（GFP） were detected under fluorescence microscopy respectively at 48 h after Lipofectamine 2000 transfection，at 96 h after adenovirus vector（Adv-GFP-NC） transfection and at 96 h after lentivirus vector transfection. U937 cells were collected for GFP-positive cells count with flow cytometry. Meanwhile，Trypan blue staining was employed to determine the cell viability. Results：GFP-positive cells were rare in Lipofectamine 2000 group and adenovirus vector group，with percentages of GFP-positive cells less than 4%. But in lentivirus group，the percentage of GFP-positive cells was about 90%（multiplicity of infection=100）. Trypan blue staining showed that the ratios of living cells were significantly higher in adenovirus group and lentivirus group than in Lipofectamine 2000 group（P<0.01）. Conclu－sions：Lentivirus，other than Lipofectamine 2000 or adenovirus，can efficiently transfect exogenous genes into U937 cells for gene ex－pression and it is an ideal vehicle for U937 cell transfection.