<p><strong>OBJECTIVE: </strong>To determine the effectiveness of developmental screening on the identification of developmental delays, early intervention (EI) referrals, and EI eligibility.</p>

<p><strong>METHODS: </strong>This randomized controlled, parallel-group trial was conducted from December 2008 to June 2010 in 4 urban pediatric practices. Children were eligible if they were &lt;30 months old, term, without congenital malformations or genetic syndromes, not in foster care, and not enrolled in EI. Children were randomized to receive 1 of the following: (1) developmental screening using Ages and Stages Questionnaire-II (ASQ-II and Modified Checklist for Autism in Toddlers (M-CHAT) with office staff assistance, (2) developmental screening using ASQ-II and M-CHAT without office staff assistance, or (3) developmental surveillance using age-appropriate milestones at well visits. Outcomes were assessed using an intention-to-treat analysis.</p>

<p><strong>RESULTS: </strong>A total of 2103 children were enrolled. Most were African-American with family incomes less than $30,000. Children in either screening arm were more likely to be identified with delays (23.0% and 26.8% vs 13.0%; P &lt; .001), referred to EI (19.9% and 17.5% vs 10.2%; P &lt; .001), and eligible for EI services (7.0% and 5.3% vs 3.0%; P &lt; .001) than children in the surveillance arm. Children in the screening arms incurred a shorter time to identification, EI referral, and EI evaluation than children in the surveillance arm.</p>

<p><strong>CONCLUSIONS: </strong>Children who participated in a developmental screening program were more likely to be identified with developmental delays, referred to EI, and eligible for EI services in a timelier fashion than children who received surveillance alone. These results support policies endorsing developmental screening.</p>