Primary reflexes are highly stereotypical, automatic movements comprising much of the motor repertoire of newborns. The current study examined rates of presence of five primary reflexes (snout, visual rooting, sucking, tactile rooting, and grasp) and variables predictive of their persistence for children with ASD (n = 35), developmental disability (n = 30), and typically developing children matched to participants with ASD on chronological age (n = 30). There was a higher prevalence of snout and visual rooting reflex among children with ASD. These data suggest that the persistence of primary reflexes holds promise as a biomarker for autism spectrum disorder (ASD).