Objective: To evaluate the current available data regarding induction of ovulation and the incidence of ovarian cancer. Design: Meta analysis Materials/Methods: A systematic review and meta analysis has been conducted. A comprehensive, literature search employing the following databases was done: Premedline, Medline, Cancerlit, Cinahl, Current contents and Biological abstracts. The search was not limited by language or year of publication. All citations were reviewed for relevance. The final group of citations was then reviewed for inclusion/exclusion criteria, quality assessment and data abstraction. This process has been completed by two independent reviewers. Discrepancies between reviewers have been resolved by consensus. Citations were supplemented by references pulled from review articles and studies as well as hand searches (10 years) of 5 key journals. We also searched for grey/unpublished literature by consultation with content experts, reviews of conference proceedings, and we attempted contact with authors. Inclusion/Exclusion criteria included: outcome: primary incident ovarian cancer of any histological type; population: women who had an explicit and reproducible diagnosis of infertility and these cases were to be compared with fertile and infertile controls; intervention/exposure: induction of ovulation by the following medications: clomiphene citrate, human menopausal gonadotropin, and gonadotropin releasing agonists. Data analyses was done using Revman 4.1 and Metaview 4.0. Cohort and case control data were analysed separately and infertile controls were used as the reference group where possible. Both fixed and random effects models were used for reasons identified in the manuscript Results: Original search revealed 2114 articles, which were reduced to 947 when limited to human, adult female. Relevance filter and manual removal of duplicates reduced the number further to 94. Inclusion/ exclusion criteria further reduced these numbers to 38. These also included : Search for unpublished literature revealed 2 studies whose results were at least partly published subsequently. Hand searching revealed 3 extra studies. When multiple publication occurred only the most recent or complete papers were included. Precision of the search strategy was 1.6% and recall was 83%. In the final quantitative analysis 3 cohort studies and 7 case control studies were included. Case control data comparing infertile treated women with general population controls:OR 1.52 (1.16, 2.01); Case control data comparing infertile treated with infertile untreated: OR 1.00 (0.68, 1.46); Cohort data comparing infertile treated to infertile untreated : RR 0.66 (0.31, 1.41). Conclusions: These data do not support an increased risk of ovarian cancer as a result of induction of ovulation. In fact, fact the results are reassuring if not encouraging. There is a trend towards protection of infertile women from ovarian cancer via induction of ovulation. Supported by: None.