Indirect evidence supports the existence of the luteinized unruptured follicle syndrome in infertile women. To seek direct evidence of oocyte retention, infertile and normal women were studied in the early and midluteal phase by visual documentation of ovulation stigma, needle aspiration of ovarian follicles, and peritoneal fluid collection for estradiol and progesterone assay. Luteal phase was confirmed by endometrial biopsy (postovulation day 2 to 8). In normal control subjects (n = 16), 25% of test cycles were stigma-negative and no oocytes were recovered. In infertile group (n = 23), 43% of test cycles were stigma-negative. Five oocytes were recovered including one from a stigma-bearing follicle. Peritoneal fluid steroid levels failed to discriminate stigma-positive from stigma-negative cycles in either group. Oocyte retention after luteinization occurs in infertile women.