Poisoning is a leading cause cause for injury and death in pediatric patients. For this reason, β-blocker ingestion has been an indication for emergency department (ED) referral and evaluation in pediatric patients even though significant clinical effects are uncommonly reported. We sought to determine whether an evidence-based triage guideline developed jointly by the American Association of Poison Control Centers, American Academy of Clinical Toxicology, and American College of Medical Toxicology safely reduces unnecessary pediatric ED visits after unintentional small dose β-blocker overdose. This was a prospective study of patients aged 0-6 years with a β-blocker ingestion managed by a regional poison center pre and postimplementation of the triage guideline. One hundred fifty-three cases met inclusion criteria. Before implementation of an evidence-based triage guideline for out-of-hospital management, 52 (67%) cases were referred for ED evaluation, and 26 (33%) cases were recommended for home observation. After guideline implementation, 38 (51%) cases were referred for ED evaluation, and 37 (49%) were recommended for home observation. No deaths occurred in either group. The triage guideline was accurately followed by poison center staff in 96% of cases after implementation. An out-of-hospital triage guideline for pediatric β-blocker overdose was accurately followed by poison center staff and safely reduced unnecessary ED referrals with a 50% increase in home observation.