Background: Osteoporosis is a progressive bone disease that is characterized by decrease in bone mass and density. The form of osteoporosis is most common in women after menopause which is referred as primary type 1 or postmenopausal osteoporosis. The World Health Organization reports 30% of postmenopausal females have osteoporosis. Studies provide evidence that strength exercise can slow the rate of loss or increase BMD in postmenopausal women, whereas in some studies, aerobic exercise showed a significantly increased bone mass. So the purpose of this study was to compare the effect of strength training program and aerobic training program to increase bone mineral density (BMD in lumbar spine and trochanter of femur) in post-menopausal women with type 1 osteoporosis. Methods: 30participants were randomly divided in equal numbers in 2 groups. Group 1(n= 15) received strength training program and group 2 (n= 15) received aerobic training program. Exercise was performed three times per week for 6 months, BMD were measured at baseline, at the 4th week, 8th week and after of 6 months of program. Result: Results of this study shows improved bone density in both groups (p≤0.05), but strength training (group1) showed more improvement of bone density in lumbar spine and femur trochanter than aerobic training group (group-2) in post-menopausal women with type 1 osteoporosis. This suggests that strength training helps to increase bone mass density compare to aerobic training program in post-menopausal women with type 1 osteoporosis. Conclusion: This study concluded that strength training program helps to increase bone mineral density in post-menopausal women with type 1 osteoporosis.