The purpose of this study is to examine the effect of cueing device by using visual , auditory or somatosensory stimuli during walking in Parkinson's disease patients. Parkinson's disease is the neurodegenerative disorders that results in characteristic motor abnormalities including impairment of gait and postural instability. The use of cueing device can improve gait of the patients by paying attention to the stimuli during walking. External rhythmical cueing is defined as 'applying temporal (rhythmical) or spatial stimuli associated with the initiation and ongoing facilitation of motor activity. Nine Parkinson's disease patients are recruited in this study. Stride length , Step length and Velocity of all patients are significantly increased and Cadence is significantly decreased in all stimuli when compared to without using stimuli. The results from this study can be useful for the patients in the future.