To evaluate masticatory function in individuals with Parkinson's disease (PD) during levodopa "on" period using new removable dental prosthesis. A total of 34 elderly individuals with PD (n = 17, mean age = 69.41 +/- 4.65 years) or without PD (n = 17, mean age = 70.71 +/- 4.65 years) were recruited for this study. Participants received new complete dentures and/or removable partial dentures. Two months after the subjects were free of any prostheses discomfort, masticatory function was assessed. A kinesiographic device was used to measure the range of jaw motion and jaw movements while chewing a silicone test material (Optocal). Masticatory performance was determined by median particle size (X-50) of the Optocal after 40 masticatory cycles. Maximum bite force was assessed by a strain sensor placed in the bilateral first molars region. Data were analyzed by t test (P < 0.05). The PD group showed a decreased range of jaw motion, longer duration and slower velocity of the masticatory cycle (P < 0.05), higher X-50 value, and lower maximum bite force (P < 0.05). PD patients have impaired masticatory function during levodopa "on" periods compared to controls. Knowledge that PD is associated with impaired masticatory function is important to dental professionals in decision making related to prosthetics and general dental treatment.