The effects of equipotent concentrations of enflurane, isoflurane, and halothane on isolated human uterine muscle have been evaluated. Three anesthetic concentrations (0.5, 1.9, and 1.5 MAC) were studied. Specimens included myometrial strips from 45 non-gravid and seven gravid uteri. Both groups of muscle strips showed significant (P less than 0.05) and progressive depression of contractility with all anesthetics. However, the extents of depression at each anesthetic level studied were similar with all drugs. Enflurane, isoflurane, and halothane are equally depressing to isolated human uterine muscle.