Blunting of the normal drop in blood pressure (BP) from day to night is emerging as a strong prognostic indicator of cardiovascular morbidity and mortality. This study evaluated the effects of natural menopause on BP dipping in African American and white women. A total of 112 women (62 premenopausal and 50 postmenopausal) took part in the study. Pre- and postmenopausal groups were comparable in terms of clinic BP, body mass index, and ethnic composition. Ambulatory BP was recorded over 24 h during a typical workday, with measurements programmed to be taken every 15 min during waking hours and every 30-minutes during sleeping hours. Nocturnal BP dipping was defined as the difference between waking and sleep BP. Waking BP did not differ by menopausal status. However, nocturnal systolic BP (SBP) and diastolic BP (DBP) dipping were attenuated in postmenopausal women, with both SBP (P < .05) and DBP (P < .05) higher during nighttime sleep in postmenopausal than in premenopausal women. Ethnicity was also related to BP dipping, with African American women tending to show blunted SBP dipping (P = .055) compared with white women; BP dipping was most blunted in postmenopausal African American women. These observations suggest that blunted nighttime BP dipping may contribute to increased cardiovascular disease risk in postmenopausal women.