Sensory and self-regulatory symptoms make up most of the comorbid symptoms in autism and are associated with increased autism severity. We validated a parent–caregiver measure of comorbid symptoms in autism, the Sense and Self-Regulation Checklist (SSC), in 265 children <6 yr with typical development (n = 138), autism (n = 99), or other developmental delay (n = 28); Cronbach’s α was .87. We report two new findings discriminating autism from other groups: (1) multifocal tactile sensory impairment, characterized by hyporeactivity to injurious stimuli and hyperreactivity to noninjurious stimuli (F[2, 262] = 86.8, p < .001) and (2) global self-regulatory delay (F[2, 262] = 122, p < .001). Both findings suggest an explanation for social delay in children with autism. The SSC reports a prevalence of sensory and self-regulatory findings approaching 100% in the autism group (96% and 98%, respectively), raising the possibility that sensory and self-regulatory difficulties represent a core part of autism.