We studied whether children with severe developmental disabilities (SDDs) who have a comorbid behavioral disorder also have higher rates of special healthcare needs (SHCNs). We used a matched-comparison control group design to establish whether SHCNs were higher in children with SDDs with behavioral disorders versus children with SDDs without behavioral disorders. Thirty-six children were matched for age (mean 12y 6mo; range 5y 2mo–18y 8mo), sex (24 males, 12 females), ethnicity (22 non-white), mental retardation level (22 moderate, eight severe, six profound), and Diagnostic and Statistical Manual of Mental Disorders, 4th edition axis I diagnosis (18 autism spectrum disorder, 10 specified syndrome, eight mental retardation not otherwise specified). Measures included the Achenbach Child Behavior Checklist, behavioral observation, health status examination, and Childhood Health Questionnaire (CHQ). Children with SDDs with behavioral disorders had significantly higher levels of SHCN, as measured by the CHQ and health status examination. Children with SDDs with behavioral disorders had a twofold higher incidence of SHCNs than children with SDDs without behavioral disorders. No difference was observed in the number or types of prescription medication that children received. The findings suggest that SHCNs contribute to the occurrence and/or intensity of behavioral disorders in children with SDD and may require interdisciplinary care coordination.