Abstract. To investigate the effects of the 1,5-benzodiazepine, clobazam, on LH secretion in normal men, LH pulsatile secretion was defined after oral administration of 40 mg of clobazam or a placebo to 6 healthy male volunteers, according to a randomized cross-over design. LH pulse frequency increased significantly from a mean of 3.8 (range 3–5 pulses/8 h after placebo, to a mean of 5 (range 4–7) pulses/8 h (P< 0.05), after clobazam. Mean LH concentrations and peak amplitudes did not change significantly. These results suggest that clobazam mediates its effects on LH secretion at the hypothalamic level by increasing the frequency of episodic GnRH release.