[영문]Objective. To evaluate the impact of Medicaid managed care organizations (MCO) on health care access for adults with disabilities (AWDs).Data Sources. Mandatory and voluntary enrollment data for AWDs in Medicaid MCOs in each county were merged with the Medical Expenditure Panel Survey and the Area Resource File for 1996?2004.Study Design. I use logit regression and two evaluation perspectives to compare access and preventive care for AWDs in Medicaid MCOs with FFS. From the state's perspective, I compare AWDs in counties with mandatory, voluntary, and no MCOs. From the enrollee's perspective, I compare AWDs who must enroll in an MCO or FFS to those who may choose between them.Principal Findings. Mandatory MCO enrollees are 24.9 percent more likely to wait qqqgt;30 minutes to see a provider, 32 percent more likely to report a problem accessing a specialist, and 10 percent less likely to receive a flu shot within the past year. These differences persist from the state evaluation perspective.Conclusions. States should not expect a dramatic change in health care access when they implement Medicaid MCOs to deliver care to the adult disabled population. However, continued attention to specialty care access is warranted for mandatory MCO enrollees.