Infection with all types of pathogens including Streptococcus Pneumoniae is a common complication for immunocompromised patients e.g. hemodialysis patients and recipients of solid organ allograft, and causes significant morbidity and mortality among these patient populations. The objectives of this study were: to assess and compare the antibody responses of renal allograft recipients and dialysis patients to pneumococcal vaccination. 14 stable dialysis patients as well as 37 kidney transplant recipients were eligible for inclusion in this trial. Participated patients receive a single 0.5-mL of 23-valent vaccine Pneumovax® administered subcutaneously in the upper extremities. The efficacy of vaccination was evaluated by measuring the antibody response to the whole vaccine. Sera were obtained prior to vaccination and 4 weeks, 6 months and 1 year after the vaccination. Prior to vaccination, mean IgG and IgG2 titers were equivalent in Dx and KTx patients (p>0.1 in both). Four weeks after vaccination, 49 out of 51 participated patients (96%) represented an increase in their anti pneumococcal IgG levels (mean 99 ± ) compared to 48 out of 51 (94%) for month 6 (mean 90 ± 59), and 38 out of 45 (85%) for the first year after vaccination (mean 73 ± 69). KTx patients kept significantly more serum IgG2 levels at months 6 and 12 after vaccination (p=0.001, p=0.03, respectively; table 1). Mean IgG values for month 6 was 9 ± 41 units lesser than month 1 post vaccination serum IgG levels. We found that patients with renal failure on hemodialysis and kidney transplantation well respond to immunization by anti pneumococcal vaccination. But, they rapidly lose their serum antibody levels during the first year after transplantation. Specifying protective levels for serum IgG and IgG2 levels in these patients would help us to more precisely follow these patients and to consider a revaccination when they failed to save the protective serum antibody level.