This study evaluated the predictive validity of the Autism Detection in Early Childhood (ADEC; Young, Autism detection in early childhood: ADEC. Australian Council of Educational Research, Camberwell, VIC 2007) and a well-established screening tool, the Childhood Autism Rating Scale (CARS; Schopler et al. The childhood autism rating scale (CARS). Western Psychological Services, Los Angeles 1988), for long term outcomes of children with ASD engaged in an early intervention program. Participants were 55 children (44 male, 11 female) aged 19-42 months (M = 33.5, SD = 5.6) at initial assessment who were followed up 2 and 6 years after their initial assessment. The ADEC and the CARS performed similarly when predicting long term outcomes such as clinical diagnostic outcome and overall adaptive functioning level. However, only the ADEC score was significantly correlated with ASD symptom severity at the 6-year follow up. Although these findings need to be replicated with additional and larger samples, this study extends our understanding of the psychometric properties of both the ADEC and the CARS.