OBJECTIVES: To compare short and long-term all cause health care resource utilization among newly diagnosed multiple sclerosis (MS) patients enrolled in Managed Medicaid or Commercial health plans.    METHODS: We used the I3 InVision Data Mart to identify continuously enrolled patients > 18 years of age with at least two ICD-9 codes for multiples sclerosis (340.xx) between the dates of June 1, 2006 and March 31, 2010. Baseline patient characteristics as well as thirty-day and 24 month all cause health care resource utilization and costs were assessed using Analysis of Variance (ANOVA) for continuous variables and Chi-squared statistics for continuous variables.  RESULTS:  Medicaid beneficiaries were more likely to have more psycho-social limitations (23.5%; p <0.0001) than their counterparts insured through commercial plans. Within the first 30 days of diagnosis, Medicaid HMO beneficiaries were more likely to be hospitalized (p = 0.006) and utilize Emergency Department services (p <0.0001). In addition, Medicaid HMO beneficiaries were 20% less likely to have a claim for a Neurologist vist and 50% less likely to be prescribed disease modifying therapies than commercial enrollees. Long-term access to medical services mirrored that observed in the short term with higher rates of hospitalization (p = 0.006) and emergency department use (p <0.001)  and less access to Neurologist (p <0.001) and disease modifying treatment (p = 0.027).    CONCLUSIONS: Opportunities exist to support newly diagnosed MS patients enrolled in Medicaid HMO plans. The development and implementation of innovative managed care strategies will ensure that Medicaid HMO beneficiaries received access to specialty care and approved treatments at the same rate as their counterparts enrolled in commercial health plans.