The American Academy of Pediatrics has recommended an algorithm for identifying children with potential developmental delays. It includes a recommendation that positive screening should result in referral for additional evaluation or intervention. Yet, it is not known whether positive screens do, in fact, influence physician referrals. The primary aim of this study was to evaluate whether positive screens from an Ages and Stages Questionnaire would prompt physicians to refer for additional evaluation or intervention as recommended by the American Academy of Pediatrics algorithm. A sample of 207 physicians read one of three hypothetical clinical vignettes describing an 18-month-old child with ambiguous language development. Vignettes differed on the presence or absence of an Ages and Stages Questionnaire score and, if a score was present, on whether the Ages and Stages Questionnaire score was positive or negative. Physicians indicated what actions they would take including whether they would refer for evaluation or intervention. Multinomial regression analyses showed physicians referred more often for further evaluation or intervention if the hypothetical Ages and Stages Questionnaire score was positive. Likewise, physicians referred less often if the Ages and Stages Questionnaire score was negative. Physicians without the Ages and Stages Questionnaire scores did not choose one action more frequently over another. In this initial investigation, the data show that physicians do refer, as recommended, when presented with positive Ages and Stages Questionnaire screens. This is important because it lends support to one critical component of the American Academy of Pediatrics developmental screening algorithm. Given the use of hypothetical vignettes in this study, it will be important to investigate whether positive Ages and Stages Questionnaire screens impact actual referrals in clinical practice.