Abstract Background Community-acquired pneumonia (CAP) is a common occurrence in childhood; consequently, evidence-based recommendations for its treatment are required. The study objective was to determine if, in previously healthy children presenting to the emergency department (ED), 5 days of high-dose amoxicillin led to noninferior rates of clinical cure at 14–21 days post-enrolment compared with 10 days of high-dose amoxicillin. Methods The SAFER study was a multicentre, randomized, parallel-group, multiple-blinded, controlled, noninferiority study, enrolling between 2012–2014 (single centre pilot) and then 2016–2019 (follow-up main study). Children aged 6 months – 10 years with all of the following were eligible: fever within 48h; a respiratory symptom/sign; a chest radiograph consistent with pneumonia as per the emergency MD; and a primary diagnosis of CAP. Children were excluded if they required hospitalization, had any medical comorbidities, or if they were already receiving beta-lactam antibiotic therapy. The intervention of interest was 5 days of high-dose amoxicillin followed by 5 days placebo. The control (standard care) arm received 5 days of high-dose amoxicillin followed by a different formulation of 5 days of high-dose amoxicillin. The primary outcome was clinical cure at 14–21 days post-enrolment. The pre-set noninferiority margin was 0.075 less than the clinical cure risk difference (1-sided 97.5% CI). Results Of the 281 participants, 119 (42%) were female; the median age was 2.6 y (25–75%ile 1.6–4.9 y). There were 140 randomized to short-course treatment and 141 to standard care. Clinical cure at 14–21 days was observed in 108/126 (86%) in the short-course arm and in 106/126 (84%) in the standard-care arm (risk difference 0.023, lower limit of 1-sided 97.5%CI -0.061). There were no participants who, after finishing amoxicillin, later deteriorated and required hospitalization for progressive CAP. Conclusion Short-course antibiotic therapy was noninferior to standard care for the treatment of previously healthy children with non-severe CAP diagnosed in Canadian EDs. Clinical practice guidelines should recommend no more than 5 days of amoxicillin for paediatric pneumonia management, in accordance with antimicrobial stewardship principles. Disclosures All Authors: No reported disclosures