► We examined the health of US children with 4 distinct developmental disabilities (DDs). ► Mutually exclusive DDs were: autism; intellectual disability; ADHD; learning disability/other delay. ► Each DD was associated with increased prevalence of many medical conditions. ► These included respiratory, gastrointestinal, dermatologic, and neurologic conditions. ► Each DD was associated with increased health service use, delays in care, and unmet needs. Studies document various associated health risks for children with developmental disabilities (DDs). Further study is needed by disability type. Using the 2006–2010 National Health Interview Surveys, we assessed the prevalence of numerous medical conditions (e.g. asthma, frequent diarrhea/colitis, seizures), health care use measures (e.g. seeing a medical specialist and >9 office visits in past year), health impact measures (e.g. needing help with personal care), and selected indicators of unmet health needs (e.g. unable to afford needed prescription medications) among a nationally representative sample of children ages 3–17 years, with and without DDs. Children in four mutually exclusive developmental disability groups: autism ( = 375), intellectual disability (ID) without autism ( = 238); attention-deficit/hyperactivity disorder (ADHD) without autism or ID ( = 2901); and learning disability (LD) or other developmental delay without ADHD, autism, or ID ( = 1955); were compared to children without DDs ( = 35,775) on each condition or health care measure of interest. Adjusted odds ratios (aORs) were calculated from weighted logistic regression models that accounted for the complex sample design. Prevalence estimates for most medical conditions examined were moderately to markedly higher for children in all four DD groups than children without DDs. Most differences were statistically significant after adjustment for child sex, age, race/ethnicity, and maternal education. Children in all DD groups also had significantly higher estimates for health care use, impact, and unmet needs measures than children without DDs. This study provides empirical evidence that children with DDs require increased pediatric and specialist services, both for their core functional deficits and concurrent medical conditions.