Menstrual blood loss was measured in 139 of 182 women who had hysteroscopy after a complaint of menorrhagia, and a preliminary diagnosis of dysfunctional uterine bleeding. Laparoscopy was also performed in 117 of these women; only 51% did not have evidence of organic pelvic disease. In those with menstrual blood loss of less than 60 ml, 75% had no abnormality, compared with only 44% and 36%, respectively, in the moderately heavy and excessively heavy groups. All those with polypoidal or submucous leiomyomas exhibited moderately heavy or excessively heavy bleeding, and so did many of those with superficial intramural or subserous myomas. The highest rate of detection of endometriosis was in women with moderately heavy blood loss, rather than excessive or normal (54% compared with 29% and 23%, respectively), and such women were more likely to have mild stage disease than severe. Other pelvic abnormalities such as adenomyosis, endometrial polyps, pelvic inflammatory disease, and some rarities were also characterized. It is contended that the era of routine, blind diagnostic curettage is now passed, and should be replaced by outpatient or office hysteroscopy accompanied by directed biopsy or curettage. © 1990.