The Autism Detection in Early Childhood (ADEC) is a brief, play-based screening tool for the assessment of autism spectrum disorder (ASD) in children aged 12-36 months. We examined the psychometric properties of the ADEC in a clinical sample of toddlers (n = 114) referred to a US pediatric hospital for assessment due to concerns of developmental delay or ASD. The ADEC (cutoff = 11) returned good sensitivity (0.93-0.94) but poorer specificity (0.62-0.64) for best estimate clinical diagnosis of ASD, and compared favorably with the ADOS-2. Internal consistency was acceptable, a = 0.80, and inter-rater reliability was high, ICC = 0.95. Results support the use of the ADEC as a clinical screen for ASD.