OBJECTIVE: Delayed antimicrobial therapy in sepsis is associated with increased hospital mortality, but the impact of antimicrobial timing on long-term outcomes is unknown. We tested the hypothesis that hourly delays to antimicrobial therapy are associated with 1-year mortality in pediatric severe sepsis. DESIGN: Retrospective observational study. SETTING: Quaternary academic pediatric intensive care unit (PICU) from February 1, 2012 to June 30, 2013. PATIENTS: One hundred sixty patients aged =21 years treated for severe sepsis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We tested the association of hourly delays from sepsis recognition to antimicrobial administration with 1-year mortality using multivariable Cox and logistic regression. Overall 1-year mortality was 24% (39 patients), of whom 46% died after index PICU discharge. Median time from sepsis recognition to antimicrobial therapy was 137 min (IQR 65-287). After adjusting for severity of illness and comorbid conditions, hourly delays up to 3 h were not associated with 1-year mortality. However, increased 1-year mortality was evident in patients who received antimicrobials =1 h (aOR 3.8, 95% CI 1.2, 11.7) or >3 h (aOR 3.5, 95% CI 1.3, 9.8) compared with patients who received antimicrobials within 1 to 3 h from sepsis recognition. For the subset of patients who survived index PICU admission, antimicrobial therapy =1 h was also associated with increased 1-year mortality (aOR 5.5, 95% CI 1.1, 27.4), while antimicrobial therapy >3 h was not associated with 1-year mortality (aOR 2.2, 95% CI 0.5, 11.0). CONCLUSIONS: Hourly delays to antimicrobial therapy, up to 3 h, were not associated with 1-year mortality in pediatric severe sepsis in this study. The finding that antimicrobial therapy =1 h from sepsis recognition was associated with increased 1-year mortality should be regarded as hypothesis-generating for future studies.