Background: We investigated the effects of a calcium-fortified beverage supplemented over 12 months on body composition in postmenopausal women (n = 37, age = 48-75 y). Methods: Body composition (total-body percent fat, % Fat(TB); abdominal percent fat, % Fat(AB)) was measured with dual energy x-ray absorptiometry. After baseline assessments, subjects were randomly assigned to a free-living control group (CTL) or the supplement group (1,125 mg Ca++/d, CAL). Dietary intake was assessed with 3-day diet records taken at baseline and 12 months (POST). Physical activity was measured using the Yale Physical Activity Survey. Results: At 12 months, the dietary calcium to protein ratio in the CAL group (32.3 +/- 15.6 mg/g) was greater than the CTL group (15.2 +/- 7.5 mg/g). There were no differences from baseline to POST between groups for changes in body weight (CAL = 0.1 +/- 3.0 kg; CTL = 0.0 +/- 2.9 kg), % Fat(TB) (CAL = 0.0 +/- 2.4%; CTL = 0.5 +/- 5.4%), % Fat(AB) (CAL = -0.4 +/- 8.7%; CTL = 0.6 +/- 8.7%), or fat mass (CAL = 1.3 +/- 2.6 kg; CTL = 1.3 +/- 2.7 kg). Conclusion: These results indicate that increasing the calcium to protein ratio over two-fold by consuming a calcium-fortified beverage for 12 months did not decrease body weight, body fat, or abdominal fat composition in postmenopausal women.