To support a fully liquid, diphtheria (D)-tetanus (T)-acellular pertussis (aP)-inactivated poliovirus (IPV)-hepatitis B (HB)-Haemophilus influenzae b (PRP-T) vaccine in Europe using a 2, 3, 4 month primary series and a booster at 11-15 months of age. Phase III, randomized, observer-blind studies in Germany and the Czech Republic. Participants who had not received HB vaccine were randomized to a 2, 3, 4 month primary series of DTaP-IPV-HB-PRP-T (group 1; N = 266) or a reconstituted DTaP-HB-IPV//PRP-T comparator (group 2; N = 263) and a booster of the same vaccine. Pneumococcal vaccine (PCV13) and rotavirus vaccine were coadministered at 2, 3, 4 months, and the booster was coadministered with PCV13. Noninferiority (group 1 versus group 2) was tested postprimary series for seroprotection rates (anti-HB and anti-PRP) and vaccine response rates (anti-pertussis toxin and anti-filamentous hemagglutinin). Safety was assessed by parental reports. Noninferiority was demonstrated with the lower bound of the 95% confidence interval for the difference (group 1 to group 2) being > -10% for each comparison. Primary series immune responses were high for all antigens and similar in each group. Prebooster antibody persistence was good, and there was a strong anamnestic response, both being similar for the investigational and control vaccines. Responses to PCV13 and rotavirus vaccine were similar in each group. There were no safety concerns. These data support the use of the DTaP-IPV-HB-PRP-T vaccine in a 2, 3, 4 month schedule without a birth dose of HB vaccine, with a booster dose in the second year of life administered with routine childhood vaccines.