Seroconversion rate following hepatitis B vaccination in patients of chronic renal failure (CRF) has been in the range of 10%-82% in various studies. Different approaches have been tried to improve seroconversion rate. We studied two schedule of hepatitis B vaccination, 0,1,2 (Group A) and 0,1,2,6 (Group B) in mild (creatinine 1.5 to 3.0 mg%), moderate (creatinine 3.0 to 6.0 mg%) and severe CRF (creatinine > 6.0 mg%). Between Oct. 93 to Oct. 95, 117 patients with CRF who were negative for HBsAg and anti-HBs were included in the study. Forty micrograms of recombinant vaccine "ENGIREX" (20 micrograms in each deltoid region) was given in both the groups. Number of cases of mild, moderate and severe CRF were 18, 15 and 42 in group A and 12, 13 and 17 in group B, respectively. One month after the last dose of vaccination, anti-HBs was measured using ELISA kit (Abbot Laboratories, India). Anti-HBs titres of > 10 IU/L were taken as criteria of positive seroconversion. In group A seroconversion rate was 87.5%, 66.6% and 35.7% in mild, moderate and severe CRF respectively while same results in group B were 100%, 77% and 36.36%, respectively. We conclude that patients of chronic renal failure should be vaccinated at very early stage of the disease using 40 micrograms of vaccine. Four doses schedule of 0,1,2,6 give better results than three doses schedule in early CRF.