Previously unrecognised temporal lobe epilepsy (TLE) was diagnosed in 11 of 16 hyposexual men. 6 had neuroendocrine abnormalities (hypogonadism in 4 and hyperprolactinaemia in 2). 4 men with hypogonadism and TLE had persistently subnormal serum testosterone, with a blunted luteinising hormone (LH) response to luteinising hormone releasing hormone (LHRH) in 2 and, in these men, unlike those with isolated hypogonadism, there was no improvement in libido or potency when parenteral testosterone was given. Men with TLE and hyperprolactinaemia had normal serum testosterone and an enhanced serum LH response after LHRH, but effective doses of the dopaminergic agonists, bromocriptine or pergolide, did not produce sustained normoprolactinaemia. In the men with neuroendocrine dysfunction and TLE the most effective therapeutic sequence was first to treat the epilepsy with anticonvulsants and then to add appropriate neuroendocrine therapy. In 2 men hormone levels became normal and sexual function was restored on anticonvulsant therapy alone.