Activation of the renin-angiotensin-aldosterone system has been hypothesized as a potential pathophysiological factor in premenstrual tension syndrome (PMS). Atenolol is a predominate beta 1-blocker which can decrease plasma renin activity and inhibit the urinary excretion of aldosterone. Sixteen women meeting provisional diagnoses of late luteal phase dysphoric disorder were treated for symptoms of PMS with atenolol (50 mg once daily) in a randomized placebo-crossover double-blind design. The data indicated significant improvements on the irritability, vigor, elation, and friendliness scores in response to atenolol compared to placebo. Significant changes were not found for several other ratings scales, indicating that atenolol improved only selected symptoms in the group as a whole. However, the women who had premenstrual tension symptoms for more than 5 years (n = 8) were improved on most of the rating scales. Atenolol decreased premenstrual plasma aldosterone to a limited extent. There was also a trend in the data toward higher luteal progesterone levels during the month subjects took atenolol. Plasma renin activity and aldosterone correlated with estrogen and progesterone levels during the placebo month but not during the active month.