SUMMARY Studies on pituitary and ovarian function as assessed by the urinary output of total gonadotrophic activity, the three classical oestrogens, pregnanediol and, in some cases, testosterone and epitestosterone, were conducted in eight patients suffering from premenstrual tension. Major abnormalities in endocrine function were not a feature of the condition. Ovulation, as judged by pregnanediol assays, was absent in seven out of the fifteen cycles investigated. Contrary to traditional belief, the symptoms of premenstrual tension could exist in the presence of cycles with anovulatory hormonal patterns.