During in vitro fertilization treatment, three types of oocyte anomalies were observed in four infertile women. These anomalies were related to (1) failure of oocyte maturation from the germinal vesicle stage of meiosis, (2) failure of polar body formation and cleavage, and (3) absence of oocytes in otherwise mature follicular aspirates. These anomalies are considered to contribute to these patients' infertility.