OBJECTIVES: Examine patient characteristics and predictors of treatment in U.S. patients with PD.   METHODS: Data were obtained from MarketScan between 1/1/2006 and 3/30/2011.  Selected patients were diagnosed with PD, with initial diagnosis date identified as index date.  Each subject was at least 35 years old and had continuous insurance coverage from 6 months prior through 12 months post index date.  Descriptive analysis of patient characteristics compared differences in continuous variables using t-tests and categorical variables using chi-square statistics.  Logistic regression examined predictors of treatment.  The pre-specified level of statistical significance was 5%.   RESULTS: There were 9,423 subjects who met study criteria. Most (n = 5,541, 58.8%) were treated with pharmacotherapy.  Treated individuals were older than untreated (57.1 vs. 56.0 years, p<0.0001), more likely to be male (p=0.0035), more likely to reside in the south and less likely to reside in the northeast (p<0.0001).  In general, the treated cohort tended to be in poorer health and have greater disability.  The treated were more likely to have been diagnosed by a neurologist and there were differences in the types of health insurance plans in which they were enrolled.   The logistic analysis examining predictors of treatment revealed odds ratios (point estimate; 95% CL) for filling a PD prescription were higher with age (1.03; 1.023 - 1.037), medical ADL (1.349; 1.170 - 1.556) or muscular skeletal (1.467; 1.329-1.618) disability, prior comorbid disease, diagnosis by a neurologist relative to a GP (1.385; 1.228 – 1.561), and being enrolled in either a POS (1.524; 1.264 – 1.837) or PPO (1.151; 1.024 – 1.293) health plan.  Factors associated with a lower likelihood of being treated included being female (0.852; 0.780 – 0.930), region of residence, and higher Charlson Comorbidity Score (0.915; 0.877 – 0.955).          CONCLUSIONS: These analyses highlighted potential age, gender and access disparities in receipt of treatment for PD.