Among a sample of 43 women with epilepsy treated for at least 2 years with valproate (n=22) or other antiepileptic drugs (AEDs) (n=21), polycystic ovary syndrome (PCOS) was diagnosed in three women, two of them were treated with valproate. Although the rate of PCOS and of menstrual disturbances, weight body mass index (BMI) and waist to hip ratio as well as fasting blood glucose levels, fasting insulin, proinsulin and C-peptide values was similar in this small sample of women treated with valproate and other AEDs, valproate exposure was associated with higher androgen levels, higher postprandial (pp) insulin and proinsulin levels, as well as lower cholesterol and low density lipoprotein (LDL) cholesterol levels. The pronounced increase in pp insulin levels during VPA treatment may indicate an effect of the fatty acid derivate VPA on pancreatic islet cells.