BACKGROUND: The impact of high blood pressure (BP) on target organs (TO) in premenopausal women is not well known. The purpose of this study was to describe gender differences in TO involvement in a cohort of young-to-middle-aged subjects screened for stage 1 hypertension and followed for 8.2 years. METHODS: Participants were 175 women and 451 men with similar age (range 18-45 years). Ambulatory BP at entry was 127.5±12.5/83.7±7.2 mm Hg in women and 131.9±10.3/81.0±7.9 mm Hg in men. Ambulatory BP, albumin excretion rate (AER), and echocardiographic data (n=489) were obtained at entry, every 5 years, and before starting antihypertensive treatment. RESULTS: Female gender was an independent predictor of final AER (p=0.01) and left ventricular mass index (LVMI) (p