An estimated 15% of children in the United States have at least one developmental delay, yet less than one-fifth of those children receive early intervention services before three years of age. Many barriers exist to implementing initial screening and referral, but screening tools can be easily incorporated into the workflow of the primary care practice with preparation. The use of a validated screening tool at regular, repeated intervals, in addition to physician surveillance at well-child visits, may improve early detection. Early intervention is effective in high-risk children and associated with improvements in cognitive and academic performance. Parent-completed tools are preferable to directly administered tools in the primary care setting because of time constraints. The most extensively evaluated parentcompleted tools are the Ages and Stages Questionnaire and the Parents' Evaluation of Developmental Status. Family physicians should be familiar with currently available screening tools and the limitations and strengths of these tools. Additional evaluations and referrals are recommended if screening suggests developmental delays are present.