The Vitaport Activity Monitor (VAM) is an ambulatory monitoring device that uses accelerometer signals to assess the quality and quantity of walking and mobility related activities in home and community. The objective of this study was to investigate the concurrent validity of the VAM and GAITRite((R)) to measure gait speed, step length and step frequency during a test of functional gait that included single, dual and multiple task components for 12 people with Parkinsons Disease (PD) and 11 comparisons participating. For PD participants, ICCs were excellent for all gait variables (ICC (2, 2)=0.92-0.99, p</=0.0001). For control participants, ICCs were good to excellent for all gait variables (ICC (2, 2)=0.74-0.94, p</=0.05). Mean score differences between the two instruments were greatest for step frequency for both PD and comparisons. The VAM is useful for objective gait measurement in the home and community.