Malnutrition in hemodialysis patients is associated with increased morbidity and mortality. The use of intradialytic parenteral nutrition (IDPN) to improve nutritional parameters has been shown to be of limited benefit in most studies. We studied the use of recombinant human growth hormone (rHuGH) in potentiating the effects of IDPN in seven hemodialysis patients dialyzed with a Kt/V of 1.03 ± 0.11 (mean ± SEM), but with evidence of malnutrition: albumin, 3.2 ± 0.18 g/dL; transferrin, 215 ± 30 mg/dL; insulin-like growth factor-1 (IGF-1),115 ± 19 ng/mL, protein catabolic rate (PCR), 0.70 ± 0.05 g/kg/d; and weight, 12.3% ± 4.0% below ideal body weight. During 6 weeks of IDPN, resulting in an additional 18 ± 4 kcal and 0.69 ± 0.03 g of protein/kg body weight per dialysis session, albumin concentration increased to 3.5 ± 0.14 g/dL (compared with baseline, P = NS), transferrin increased to 279 ± 36 mg/dL (P < 0.002), IGF-1 increased to 152 ± 32 ng/mL (P = NS), and PCR increased to 0.81 ± 0.04 g/kg/d (P = NS). During the next 6 weeks, IDPN administration was continued and rHuGH, at a dose of 5 mg subcutaneously during each dialysis, was added to the regimen. This resulted in an increase in albumin concentration to 3.8 ± 0.08 g/dL (P < 0.04 0.04 compared with end of IDPN phase), an increase in transferrin to 298 ± 41 mg/dL (P = NS compared with end of IDPN phase), and an increase in IGF-1 to 212 ± 45 ng/mL (P = 0.05 compared with end of IDPN phase). In addition, during the rHuGH administration phase, PCR decreased from 0.81 ± 0.04 g/kg/d at the end of the IDPN phase to 0.67 ± 0.03 g/kg/d, consistent with a decrease in intradialytic urea appearance. There were no statistically significant changes in anthropometric parameters during the study period. We conclude that the addition of rHuGH to an IDPN regimen potentiates the effects of IDPN and may improve malnutrition parameters in hemodialysis patients. Nevertheless, in the absence of a larger population and a placebo-controlled randomized designed study, these results should be considered as preliminary and in need of further confirmation. © 1993, National Kidney Foundation. All rights reserved. All rights reserved.