Rapid-rate transcranial magnetic stimulation (rTMS) was administered to 10 healthy volunteers on different days over the right or left prefrontal cortex, midfrontal cortex, occipital cortex, or cerebellum. Mood (self-rated), reaction time, and hormone levels were serially measured. Consistent with a previous study, comparison of hemispheres revealed significant associations with decreased happiness after left prefrontal rTMS and decreased sadness after right prefrontal rTMS. Stimulation of all three prefrontal regions, but not the occipital or cerebellar regions, was associated with increases in serum thyroid-stimulating hormone. There was no effect on serum prolactin. rTMS applied to prefrontal cortex is safe and well tolerated and produces regionally and laterally specific changes in mood and neuroendocrine measures in healthy adults. rTMS is a promising tool for investigating prefrontal cortex functions.