Medroxyprogesterone acetate (MPA), a synthetic progesterone, was added to the antiepileptic drug regimen of 14 women who had uncontrolled seizures. Of the 11 women who developed amenorrhea, 7 reported fewer seizures during MPA therapy. Overall reductions in seizure frequency averaged 30% (n = 11), declining from a baseline 8.3 ± 5.8 seizures per month to 5.1 ± 4.1 seizures per month (p = 0.02). No serious side effects were encountered, but spotting was common. These preliminary data suggest further evaluation of MPA for catamenial seizures.