OBJECTIVES: Evaluate diagnosis and treatment initiation patterns in Parkinson’s disease (PD) based upon age.  METHODS: Data were obtained from the i3 InVisionTM Data Mart database from January 1, 2006 through March 30, 2011.  Patients were diagnosed with PD (initial diagnosis identified as index date), had continuous insurance coverage from 6 months prior through 12 months post index date and were at least 35 years old. Cohorts were divided into those under 65 and over 65 years of age.  These analyses are descriptive, with continuous variables examined using t-tests and categorical variables examined using chi-square statistics.  RESULTS: A total of 5,967 patients fit the inclusion criteria. More individuals (58.22%) were age 65 or older, and in worse physical health, evidenced by a significantly higher pre-period Charlson score (1.52 vs. 0.77; P<0.0001) and had higher rates of pre-period cerebrovascular disease (21.53% vs. 9.07%; P<0.0001), cardiovascular disease (22.86% vs. 8.10%; P<0.0001), dementia (10.22% vs. 1.60%; P<0.0001), diabetes (22.77% vs. 14.64%; P<0.0001), hypertension (56.99% vs. 35.10%; P<0.0001), and psychoses (15.03% vs. 9.51%; P<0.0001).  Individuals age 65+ were significantly less likely to be treated with PD medication (35.69% vs. 46.21%; P<0.0001), and more likely to be diagnosed by a neurologist (61.37% vs. 48.29%; P<0.0001).  Older individuals were more likely to be initially prescribed carbidopa/levodopa (44.27% vs. 20.83%; P<0.0001), a catechol o-methyltransferase inhibitor (5.08% vs. 2.25%; P=0.0003), or carbidopa/levodopa/entacapone (10.81% vs. 6.34%; P<0.0001), but significantly less likely to be initially prescribed a dopamine agonist (32.42% vs. 47.14%; P<0.0001), a monamine oxidase B inhibitor (12.50% vs. 24.31%; P<0.0001), or an anticholinergic (3.31% vs. 6.83%; P<0.0001).  There was no significant difference between rates of switching from initially prescribed medication (18.63% vs. 21.53%; P=0.0767), although younger individuals were more likely to add an additional class of therapy (18.40% vs. 13.15%; P=0.0004). CONCLUSIONS: These analyses highlighted potential age disparities in treatment patterns.