In the event of unexpectedly finding an ovarian cyst at the time of laparoscopy, serum CA 125 assay is helpful in deciding the subsequent management of the cyst. It is unclear, however, when the CA 125 should be checked. There has been some debate as to the effect of laparoscopy on the level of CA 125 and whilst it is widely accepted that laparotomy will increase the level of CA 125 the effects of laparoscopy have not been investigated until now. Pre and post operative CA 125 levels were measured in 20 patients undergoing simple laparoscopic surgery. Analysis of the results indicate that simple laparoscopic procedures have an insignificant effect on serum CA 125 levels checked in the immediate post operative period.