The main aim of this study was to compare the response to trivalent inactivated influenza vaccine in children who received a kidney transplant and were on steroid-free versus steroid-based immunosuppression. Groups: 1. Kidney transplant recipients on steroid-free immunosuppression (n=27); 2. Kidney transplant recipients on steroid-based immunosuppression (n=39); 3. Healthy controls (n=21). Hemagglutination inhibition titers against 2007-2008 A/H1N1 and A/H3N2 and B strains were measured before and 8 weeks postvaccination. Postvaccination geometric mean titers to A/H1N1 were significantly lower among both transplant groups than controls (p=0.025 and 0.015, respectively). Postvaccination titers to H3N2 and B strains were not statistically different between groups. Proportions of participants developing seroprotection were not different among groups. Both kidney transplant groups seroconverted less than controls for A/H1N1 (p=0.0002) and were no different from controls for B. For A/H3N2, the steroid-free group had the weakest seroconversion (p=0.008), possibly due to mycophenolate-enhanced exposure and a younger age. Overall, children after kidney transplantation demonstrated a good serologic response to the inactivated influenza vaccine although somewhat lower than controls. Steroid-free immunosuppression did not seem to present an advantage in antibody response. Data on inactivated influenza vaccine safety and efficacy was collected and demonstrated absence of acute rejection or laboratory-proven influenza for 6 months postvaccination.