In January 2012, Argentina included universal pneumococcal vaccination in the routine childhood vaccination program using a 13-valent pneumococcal conjugate vaccine (PCV13). A 2 + 1 schedule (2 doses in the first year of life and a booster dose at 12 months of age) in children aged <2 years and 2-dose catch-up immunization in children aged 13 to 24 months was administered during the first year of vaccine introduction. The purpose of this study was to assess the burdens of invasive pneumococcal disease (IPD) and/or community-acquired pneumonia (CAP) in hospitalized children younger than 5 years during the first 2 years of the program compared to those in the prevaccination period in our setting.