Having a consistent source of medical care may facilitate diagnosis of autism spectrum disorders (ASD). This study examined predictors of age of ASD diagnosis using data from the 2011-2012 National Survey of Children's Health. Using multiple linear regression analysis, age of diagnosis was predicted by race, ASD severity, having a consistent source of care (CSC), and the interaction between these variables after controlling for birth cohort, birth order, poverty level, parental education, and health insurance. While African American children were diagnosed earlier than Caucasians, this effect was moderated by ASD severity and CSC. Having a CSC predicted earlier diagnosis for Caucasian but not African American children. Both physician and parent behaviors may contribute to diagnostic delays in minority children.