Physical activity is generally thought to be beneficial to individuals with Parkinson's disease (PD). There is, however, limited information regarding current rates of physical activity among individuals with PD, possibly due to a lack of well-validated measurement tools. In the current study we sampled 63 individuals (31 women) living with PD between the ages of 52 and 87 (M = 70.97 years, SD = 7.53), and evaluated the amount of physical activity in which they engaged over a 7-day period using a modified form of the Physical Activity Scale for Individuals with Physical Disabilities (PASIPD). The PASIPD was demonstrated to be a reliable measure within this population, with three theoretically defensible factors: (1) housework and home-based outdoor activities; (2) recreational and fitness activities; and (3) occupational activities. These results suggest that the PASIPD may be useful for monitoring physical activity involvement among individuals with PD, particularly within large-scale questionnaire-based studies.