Sexual dysfunction has been reported to be common among women with epilepsy. Controlled studies, quantitative data, and investigations of potentially contributory factors, however, have been few. The purpose of this investigation was to determine if (1) sexual dysfunction is unusually common among women with partial seizures of temporal lobe origin (TLE), and (2) sexual dysfunction varies in relation to the laterality of EEG epileptiform discharges, antiepileptic drug use, and serum gonadal steroid levels. This controlled prospective investigation used a quantitative sexual rating scale and reproductive hormone measures to compare sexual dysfunction in women with left and right unilateral temporolimbic epilepsy and controls. Sexual dysfunction scores were significantly higher in women with TLE, and sexual dysfunction affected substantially more women with epilepsy than controls. Women with right-sided foci were affected more than women with left-sided foci. There was a significant inverse correlation between sexual dysfunction and bioactive testosterone levels in women with epilepsy as well as in controls. Serum estradiol was lower in women with TLE but did not correlate significantly with overall sexual dysfunction. The findings suggest that sexual dysfunction is significantly more common in women with right-sided epileptiform discharges than in controls and is inversely correlated with bioactive testosterone levels. The value of hormonal replacement or supplementation remains to be explored.