Gait disturbance is a serious problem in Parkinson's disease (PD). Exercise therapy is used to alleviate this complaint. We investigated the effects of a videotaped arm swinging-based home exercise program on gait in PD patients. The subjects included 25 outpatients aged between 55 and 77 years (average age 68.9 years) with PD in Hoehn and Yahr stages II-IV. We prepared a master video tape in which a trainer was shown to be performing an arm swinging exercise or steps in synchrony with a metronome. The exercise menu consisted of 4 parts : arm swinging in a seated position, arm swinging in an upright position without stepping, arm swinging with stepping, and walking on the floor or taking a walk. The patients performed the arm swinging exercise while watching a video tape everyday for a period of 3.4 weeks. Of the 25 patients, 22 completed the exercise program. Following the program, these patients showed significant improvements in their walking times for a 20m walk (10 m, return, 10 m) (before/after=29.6/24.3 sec, p=0.002) and in the step length (before/after=43.7/50.1 cm, p<0.001). Frozen gait was a negative factor to complete the programs. Improvement of gait speed after the exercise was related with less frequency of cadence. Loss of arm swinging in PD may be associated with a disturbance in the internal rhythm formation process. Arm swinging exercises are one of the exercise methods that use rhythmic cues. This study suggests that a videotaped arm swinging-based home exercise therapy is effective in such patients.