Background/Aims: Growth hormone (GH) resistance leads to enhanced protein catabolism and contributes to the malnutrition of patients with chronic renal failure (CRF). In short-term trials anabolic effects of rhGH therapy have been demonstrated in patients on chronic hemodialysis. Methods: This study was initiated to determine the effects of 12 months of rhGH therapy on polymorphonuclear leukocyte (PMNL) function as well as on nutritional and anthropometric parameters. 0.125 IU/kg rhGH was given 3 times a week during the first 4 weeks and 0.25 IU/kg thereafter to 19 malnourished hemodialysis patients with a mean age of 59.3 ± 13.4 years. Results: Insulin-like growth factor I (IGF-I) concentrations rose significantly from 169.2 ± 95.6 to 262.9 ± 144.4 ng/ml (p < 0.01) in the first 3 months, but declined thereafter. Phagocytic activity of PMNLs also increased significantly in response to rhGH therapy and this activation remained stable over the whole 12-month period. Other parameters of PMNL function were not influenced by rhGH therapy. In addition, nutritional parameters such as albumin, prealbumin, transferrin, cholesterol, HDL-cholesterol, cholinesterase, predialytic creatinine and blood urea nitrogen were not affected by rhGH therapy. A decline of total body fat (TBF) was observed after 3 and 9 months of rhGH therapy (17.5 ± 10 vs. 16.7 ± 10% after 3 months, p < 0.017 and 16.8 ± 8.7% after 9 months, p < 0.049), whereas lean body mass remained stable. Conclusions: Twelve months of rhGH therapy caused a significant increase in IGF-I levels, stimulated phagocytic activity of PMNLs and induced a decline of TBF. Other anthropometric and nutritional parameters were not affected, which might be related to the persistence of GH resistance.