This study examined the performance of the First Year Inventory (FYI; version 2.0), a community-normed parent-reported screening instrument, in a high-risk (HR) sample of 12-month-olds with older siblings diagnosed with autism spectrum disorder (ASD). The FYI 2.0 was completed by parents of 86 HR infants and 35 low-risk control infants at age 12 months, followed by clinical diagnosis at 36 months. HR infants later diagnosed with ASD had significantly higher FYI 2.0 risk scores in both the social-communication and sensory-regulatory domains than typically developing infants. New FYI 2.0 cutoff scores for HR sample were explored by evaluating various cutoff options after considering tradeoffs between sensitivity and specificity and sample characteristics.