Two studies were conducted to examine the use of the Taiwanese version of the Screening Tool for Autism in Two-Year-Olds for detecting autism spectrum disorder in toddlers aged 18-24 months. Study 1 used receiver operating characteristics to select a cutoff score for the Taiwanese version of the Screening Tool for Autism in Two-Year-Olds. It involved two groups of 16 toddlers each, one group with toddlers having autism spectrum disorder and the other group with chronological and mental age-matched toddlers with developmental delay. The result suggested that a cutoff of 2.50 would yield high sensitivity and specificity. In Study 2, we recruited 136 toddlers-30 with autism spectrum disorder, 33 with mild-autism spectrum disorder, and 73 with developmental delay. Using 2.50 as the cutoff score, the concurrent agreement between Taiwanese version of the Screening Tool for Autism in Two-Year-Olds risk and clinical diagnosis and Autism Diagnostic Observation Schedule yielded high sensitivity and specificity. The results of this study indicated that the Taiwanese version of the Screening Tool for Autism in Two-Year-Olds can be used as a Level 2 autism-specific screening tool for the 18-24 months age group.