The monocyte migration induced by the media conditioned by cultured rabbit peritoneal exudate macrophages was assayed by micropore filter method using modified Boyden chamber.Influence of anti-MCP-1 antibody on monocyte migration was observed as well.Meanwhile,we examined the expression of MCP-1 mRNA in the macrophages by Northern blot analysis. Results Cultured rabbit peritoneal exudate macrophages produced a factor that was chemotactic for monocytes,and the activity due to chemotaxis and not chemokinesis,the chemotactic activity was markedly inhibited by anti-MCP-1 antibody. MCP-1 mRNA was expressed by the macrophages.Conclusions Macrophages can produce MCP-1 and play an important role in atherogenesis through attracting monocytes to migrate into subendothelial space.