To assess the additive effect of a bisphosphonate on testosterone replacement therapy on bone markers and bone mineral density (BMD) in aged hypogonadal men 12 subjects with decreased BMD, 58-72 years, were treated with testosterone and either placebo (T+P) or alendronate (T+A) for 2 years. In T+P group bone measures had declined in a none-significant rate. However, in the T+A group the decline in the levels of serum bone specific alkaline phosphatase (BSAP) were significant, at 3, 6, 12, 18, and 24 months p<0.03, p<0.0004, p<0.007, p<0.05, and p<0.004, respectively. The difference between the two groups became significant at 6 months, p< 0.006. The decline in the urine DPD/Cr in T+A group became significant at 18 and 24 months, p=0.02 & p=0.05, respectively and the difference between the two groups was significant at 18 months, p<0.008. No significant decline were noted in the levels of urinary PYD/Cr in either group but a significant difference noted between the two groups at 6 and 18 months, P<0.02 for both. Moreover, there was a significant reverse correlation between the baseline testosterone and BSAP at 6 and 12 months (p<0.01 & p=0.05, respectively), with osteocalcin at 6 and 18 months (p<0.02 for both), and with urine DPD/Cr at 18 months, p<0.04. The BMD increased in every patient at 24 months. Triglycerides and cholesterol significantly decreased at 3 months. While serum triglycerides remained significantly low during the study but the decline in cholesterol levels were not significant thereafter. In summary, we found that the addition of bisphosphonate to testosterone has a significant role on bone metabolism. In addition testosterone replacement has a healthy effect on lipid profile.