A 42-year-old woman with Stage IA, grade 3 clear cell ovarian carcinoma arising within an endometrioma after multiple ovarian stimulation attempts was a unique case from a total of 900 patients who underwent laparoscopy for infertility and pelvic pain between 1996 and 2002 at Yale University. Her previous treatments included two laparoscopic cystectomies for left ovarian endometriomas and four cycles of IVF-ET that resulted in one miscarriage and two successful pregnancies. Although it has been suggested that controlled ovarian hyperstimulation may predispose to the development of ovarian cancer, more recent studies postulate a protective effect if fertility treatments ultimately result in successful pregnancy. Our unusual case serves as a reminder that clear cell adenocarcinoma may coexist with endometriosis, and that parity does not necessarily protect infertility patients against the development of ovarian cancer.