Recent reports on growth hormone (GH) therapy have shown that GH has various beneficial effects in GH deficient adults. In most of these studies, GH was administered daily. Because GH is still expensive and has to be delivered by subcutaneous injection, we studied the 6-month therapeutic effects of thrice weekly GH injection therapy and compared it with daily therapy. Twenty eight adult patients with GH deficiency were randomly assigned into group 1 (ten cases, thrice weekly injections of GH), group 2 (nine cases, daily injections), and group 3 (nine cases, placebo injections). Lean body mass, serum basal GH levels, and insulin-like growth factor 1 levels significantly increased after six months of GH therapy in both groups 1 and 2. According to computed tomography, the mean mid-thigh muscle mass significantly increased in group 1, while the visceral fat mass significantly decreased in group 2. GH levels significantly increased exercise rate-pressure product and hand grip strength only in group 1. These results suggest that thrice weekly injections of GH are as effective as daily injections in GH deficient adults.