BackgroundOvarian pregnancy is a rare form of ectopic pregnancy increasing in incidence. It is difficult to diagnose clinically and even intraoperatively. Although much effort has focused on appropriate diagnosis and management, it is difficult or nearly impossible because some pitfalls associated with this condition are inherent and are prone to be overlooked.CaseThis case was initially diagnosed as a tubal pregnancy with abortion that occurred during previous laparoscopic surgery, but proved to be ovarian pregnancy 3 weeks later complicated with massive hemoperitoneum.ConclusionsThe following steps are recommended: 1) the removal of any suspected ovarian mass, or at least a biopsy from the free edge of the ovarian cyst wall; 2) a longer follow-up period in the postoperative monitoring of /31-hCG level; 3) the complete removal of all the specimens during operation be mandatory, especially if the specimen is fragmented; 4) the careful use of chromotubation for the exclusive diagnosis of ectopic pregnancy.