Objectives: The research aims to investigate a) the effect of adulthood health problems on the three dimensions of disability(i.e., mental functions, activity capacity in daily movement, and participation frequency), b) the effect of formal/informal supports on the three dimensions of disability, and c) the moderating effects of formal/informal supports. Methods: Nationally representative sample of 1,075 adults with developmental disabilities aged 18 and over are analyzed from ‘2011 Policy Recommendations for Supporting People with Developmental Disabilities and their Families Based on a Needs Assessment Survey’. Based on the International Classification of Functioning, Disability and Health, health condition is operationalized as the number of adulthood onset health problems; body function as mental functions(MF); activity as activity capacity in daily movement(AC); and participation as participation frequency in social activities(PF). Structural equation modeling is employed for the analysis. Results: The findings revealed that the number of adulthood health problems negatively affected MF and AC. Community services and informal support had positive influences on AC and PF. Finally, community services showed the moderating effect in the association between the adulthood health problems and PF. Conclusions: Theoretical, practical and policy implications regarding health promotion and decrease in disability were further addressed.