Objective. To evaluate outcomes of a registered nurse-led care management intervention for disabled Medicaid beneficiaries with high health care costs. Data Sources/Study Setting. Washington State Department of Social and Health Services Client Outcomes Database, 2008Database, -2011 Study Design. In a randomized controlled trial with intent-to-treat analysis, outcomes were compared for the intervention (n = 557) and control groups (n = 563). A quasiexperimental subanalysis compared outcomes for program participants (n = 251) and propensity score-matched controls (n = 251). Data Collection/Extraction Methods. Administrative data were linked to describe costs and use of health services, criminal activity, homelessness, and death. Principal Findings. In the intent-to-treat analysis, the intervention group had higher odds of outpatient mental health service use and higher prescription drug costs than controls in the postperiod. In the subanalysis, participants had fewer unplanned hospital admissions and lower associated costs; higher prescription drug costs; higher odds of long-term care service use; higher drug/alcohol treatment costs; and lower odds of homelessness. Conclusions. We found no health care cost savings for disabled Medicaid beneficiaries randomized to intensive care management. Among participants, care management may have the potential to increase access to needed care, slow growth in the number and therefore cost of unplanned hospitalizations, and prevent homelessness. These findings apply to start-up care management programs targeted at high-cost, high-risk Medicaid populations.