AIM: To study the overall protein expression changes induced by oxidized low-density lipoprotein (ox-LDL) in the U937 foam cells. METHODS: Foam cell model was established by incubating the human monoblastic leukemia (U937) cells with ox-LDL. Each protein samples in U937 control cells and U937 foam cells were separated by two-dimensional gel electrophoresis (2-DE). After the gels were stained by silver staining method, the images were analyzed by PDquest 2D-image-analysis software (Bio-Rad). Some of the spots were available via the Internet with links to the U937 proteomic map provided from the ExPASy Proteomics server. RESULTS: Using 2-DE, the overall protein map was obtained, in which 150 spots were matched with the control gel (match ratio: 75 %). Compared with U937 cells, 37 spots significantly changed in the foam cells (P<0.05), among which the expression levels in 28 spots increased and those in 9 spots decreased. Especially, 8 spots in U937 cells were absent in the foam cells, while 11 spots in the foam cells were absent in the control cells. CONCLUSION: The changed protein profiles induced by ox-LDL in U937 foam cells were established to support the functional studies on the macrophage-derived foam cells in atherosclerotic pathological states.