We compared nonphysician and physician health care providers' knowledge of the pharmacological management of Parkinson's disease (PD) and their preferences for referring PD patients to specialists. A survey instrument was mailed in 2003 to all geriatric, neurology, mental health, and primary care physicians, nurse practitioners, and physician assistants in the Pacific Northwest Veterans Health Administration (n = 503). The instrument contained questions about recommended practices for the pharmacotherapy of PD and two clinical scenarios followed by questions regarding referral preferences. The overall response rate was 74%. Nonphysicians answered 46% and physicians answered 50% of questions about PD pharmacotherapy in agreement with recommended clinical practice (P = 0.14). Nonphysician and physician providers did not differ in their preference to refer a PD patient to a specialist for management, but nonphysician providers were more likely to refer a patient to a specialist for diagnostic confirmation odds ratio: 3.03; 95% confidence interval: 1.67, 5.51). Given trends for more nonphysician provider autonomy in patient care, it is reassuring that nonphysician providers have similar knowledge of PD pharmacotherapy as physicians. Policies to substitute nonphysician providers for physician providers may increase referrals to specialty providers for diagnostic confirmation.