Variation of seizure frequency during the menstrual cycle has been attributed in part to an antiepileptic action of progesterone reducing seizure frequency during the luteal phase, but studies have not distinguished patients with primary generalized, secondary generalized and absence epilepsies. We describe a patient whose absence seizure frequency increased when she was administered progesterone. This indicates that, in contrast to secondarily generalized seizures, progesterone may exacerbate absence seizures.