This study was undertaken to determine the proportion of persons primarily with developmental disabilities who encounter difficulties accessing dental care in Ontario, to identify perceived barriers to accessing dental care and to determine if persons with disabilities and their caregivers believe that oral health is important.Community organizations providing services mainly to persons with developmental disabilities in Ontario were recruited to circulate a questionnaire to their members by mail or the Internet. Fourteen organizations mailed out a total of 1,755 paper questionnaires in autumn 2006, of which 420 (23.9%) were returned; in addition, 236 Internet questionnaires were returned.Of the 656 paper and Internet responses, 634 were deemed valid. Most of the respondents had developmental disabilities. Almost three-quarters of respondents (464 [73.2%] ) reported being able to access dental services in Ontario. Personal (internal) factors were more likely to represent barriers to dental care than external factors.The majority of persons with disabilities and most caregivers believed that oral health is important for overall health.