OBJECTIVE To determine whether there is an association between the level of habitual physical activity, body composition and anthropometric and metabolic variables in postmenopausal patients before and after hormone replacement therapy (HRT). METHODS Thirty-four healthy, recent postmenopausal women (50+/-2.7 years; 23.8+/-10 months since menopause) consulting for symptoms of estrogen deficiency were included in the study. Anthropometric assessment, percent of body fat (BF) estimated by skinfold measures, and metabolic evaluation were performed before and 4 months after the start of HRT, which included non-oral or low-dose oral preparations. The status of physical activity was defined by counting steps with a pedometer. Patients were stratified as active (6000 steps ore more per day) or inactive (fewer than 6000 steps per day). Results are expressed as mean+/-SD or median and interquartile range. log 10 transformation was used to normalize the distribution of non-Gaussian variables. ANOVA for repeated measures was performed for the active and inactive groups, before and after HT. Pearson correlation coefficient was used to investigate the relationship between anthropometric and metabolic variables and habitual physical activity. RESULTS BMI and BF did not change with HRT in comparison with baseline. In contrast, a decline was observed in waist circumference (WC) and waist to hip ratio (WHR) after HRT in both active and inactive women (P<0.01). While triglycerides and glucose did not change after HRT, total and LDL-cholesterol decreased from baseline. In contrast, after HRT, active patients were found to have lower BF than inactive women (active: 25.4+/-2.5; inactive: 26.6+/-2, P=0.01). There was a significant negative correlation between habitual physical activity (number of steps per day) and BF (r=-0.36, P=0.04). After HRT, when only active patients were considered, a significant negative correlation was found between the number of steps and WC (r=-0.42, P=0.04) and WHR (r= -0.58, P=0.03). CONCLUSIONS Habitual physical activity plays a major role in preserving a favorable cardiovascular profile in postmenopausal patients using HRT.