Aim To study the effect of monocyte chemotactic protein-1 (MCP-1) on the proliferation of human umbilical vascular smooth muscle cells (hUVSMC). Methods hUVSMC were cultured in vitro. Growth-arrested hUVSMC were stimulated with different concentrations of MCP-1 (0.1, 1.0, 10 and 100 μg/L). The response of hUVSMC to these treatments was observed in comparison with that of platelete derived growth factor (PDGF). The proliferation of hUVSMC was evaluated by cell counting, MTT assay and flow cytometry. The expression of c-fos mRNA was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). Results MCP-1 stimulated the proliferation of hUVSMC in a dose-dependent-manner. Compared with PDGF, the effect of MCP-1 at high concentration was significant (p<0.01). Meanwhile, MCP-1 induced the expression of c-fos mRNA. Conclusions MCP-1 could promote the proliferation of hUVSMC and the expression of c-fos mRNA. The effect of MCP-1 at high concentration was more significant than that of PDGF. MCP-1 may exert its effects on cells through c-fos.