Abdomino-pelvic adhesions arise from infection, endometriosis, or peritoneal injury during surgery, and represent a significant source of morbidity in women of reproductive age. Monocyte chemotactic protein-1 (MCP-1) plays a role in the chemotaxis of mononuclear cells and fibroblasts in a murine wound repair model. To evaluate the role of MCP-1 in intraperitoneal adhesion formation, we investigated peritoneal fluid MCP-1 levels of women undergoing laparoscopy. Patients without endometriosis were divided into two groups: normal fertile women undergoing bilateral tubal ligation without intraperitoneal adhesions (n=14) and women with pelvic adhesions (n=8). Patients with endometriosis were arranged into two groups: women with (n=17) and without (n=17) adhesions. Peritoneal fluid MCP-1 levels were quantified using an enzyme-linked immunosorbent assay (ELISA). Peritoneal biopsy samples were immunostained for the detection of MCP-1 protein and macrophages, and were also processed for the presence of MCP-1 mRNA expression. Among women without endometriosis, the median peritoneal fluid MCP-1 level was 144 pg/ml (range 54-261) in women without adhesions and was 336 pg/ml (range 130-2494) in women with adhesions (P=0.01). There was a significant correlation between adhesion scores and MCP-1 levels (r=0.50; P=0.018). Among women with endometriosis, peritoneal fluid MCP-1 levels significantly correlated with the stage of the disease. The presence or absence of adhesions did not significantly affect the peritoneal fluid MCP-1 levels in this group of women. In summary, we have found that women with adhesions have elevated peritoneal fluid MCP-1 levels. However, we were not able to show an incremental effect of adhesions on peritoneal fluid MCP-1 levels of patients with endometriosis. Thus, we conclude that factors besides the intraperitoneal adhesions contribute to the elevated peritoneal fluid MCP-1 levels in patients with endometriosis.