The effect on fertilization and development of local anesthetics routinely used during ultrasound-guided oocyte retrieval in women undergoing in vitro fertilization was examined in a mouse in vitro fertilization system. Mouse oocytes were exposed in vitro to lidocaine, chloroprocaine, and bupivacaine at concentrations of 0 (control), 0.01, 0.1, 1.0, 10.0, 100.0 micrograms/mL for 30 min, washed, and then inseminated. In vitro oocyte fertilization at 24 and 48 h and embryo development at 72 h were determined. Bupivacaine adversely affected mouse in vitro fertilization and embryo development only at the highest exposure concentration, 100 micrograms/mL, while lidocaine and chloroprocaine produced adverse effects at concentrations as low as 1.0 and 0.1 microgram/mL, respectively. Furthermore, an adverse dose-related effect on fertilization and embryo development was shown for lidocaine and chloroprocaine, but not for bupivacaine. These data demonstrate that the local anesthetics, lidocaine (L), chloroprocaine (C), and bupivacaine (B), adversely affect mouse in vitro fertilization and embryo development in the order of C greater than L greater than B.