We will conduct a randomized, placebo-controlled trial to test the hypothesis that supplementation with testosterone improves rehabilitation outcomes in deconditioned older men. Specifically, we will screen all hospitalized older men with delayed discharge from the hospital (> 7 day hospital stay). Men who have at least one new impairment in their ability to perform activities of daily living (e.g., inability to walk), low serum testosterone concentration, and no contraindications (e.g., prostate or breast cancer) will be offered the opportunity to participate. Study participants will be randomized to receive either testosterone (5 mg transdermally each night) or placebo (matching transdermal patch) daily in a double-blind fashion for the duration of their hospital course (expected average duration of study is 29 days). Subjects will then receive their rehabilitation as usual, with all members of the health care team blinded as to whether the subject is receiving testosterone or placebo. At baseline, weekly, at discharge, and at 6 and 12 months after discharge, subjects will be assessed using validated measures (i.e., Functional Independence Measure - FIM). Our hypothesis is that testosterone supplementation, as an adjunct to traditional rehabilitation therapy, will improve rehabilitation outcomes.