The long-term objective of this study is to test the hypothesis that the combined therapy shows a greater bone effect than does either treatment given alone. Our specific aim is to conduct a 3.5 year, randomized, double-blind, controlled trial of low-dose, continuous HRT combined with alendronate, 10 mg/d (ALN), in three groups (72 people per group) of estrogen-deprived postmenopausal women over age 60. We will give Group 1 low-dose HRT, Group 2 ALN, and Group 3 both low-dose HRT and ALN. We will give calcium and vitamin D supplements to people in all three groups.