We investigated intradermal hepatitis B (HBV) vaccination in 24 renal transplant recipients who failed to develop hepatitis B surface antibody (anti-HBs) with intramuscular (i.m.) vaccination. All patients received recombinant HBV vaccine 5 microg intradermally every 2 weeks for 8 doses. Nine patients developed protective levels of anti-HBs (> 10 miu/mL) and two patients developed low levels of anti-HBs (4-6 miu/mL), giving an overall initial response rate of 45.8%. A booster of 40 microg was administered intramuscularly after 1 year. All initial responders developed an anti-HBs response (322.6 +/- 92.0 miu/mL). In addition, four patients who did not respond initially to the intradermal vaccination seroconverted after the booster. Responders (62.5%) and nonresponders had comparable age, gender, immunosuppressive medications, and duration of transplant. In conclusion, renal transplant patients who fail to respond to intramuscular HBV vaccination may benefit from intradermal vaccination followed by an intramuscular booster.