There is no adequate data in the medical literature defining serum CA-125 levels after laparotomy. Therefore we designed this prospective study to evaluate the effects of laparotomy for hysterectomy on serum CA-125 levels. Ninety-four women (mean age 44.6 +/- 6.9 years) were included in the study between January, 2001 and April, 2003. Hysterectomies were performed in patients with chronic pelvic pain, dysfunctional uterine bleeding and myoma uteri. Mean serum CA-125 levels of the patient, before and after laparotomy were 16.29 +/- 8.11 U/ml and 16.37 +/- 8.05 U/ml, respectively. The change in serum CA-125 levels prior to the operation was statistically insignificant when compared with the levels obtained at 24 hours after laparotomy (p > 0.05). We found that laparotomy for hysterectomy did not change the levels of CA-125 at the 24th hour after the operation, indicating either serum CA-125 levels are not correlated, at least within 24 hours, with peritoneal irritation or peritoneal irritation was minimal or absent in our operations.