Objective: To investigate the feasibility and effectiveness of six weeks of home-based treadmill training in people with mild Parkinsons disease. Design: Pilot randomized controlled trial of a six-week intervention followed by a further six weeks follow-up. Setting: Home-based treadmill training with outcome measures taken at a hospital clinic. Participants: Twenty cognitively intact participants with mild Parkinsons disease and gait disturbance. Two participants from the treadmill training group and one from the control group dropped out. Interventions: The treadmill training group undertook a semi-supervised home-based programme of treadmill walking for 2040 minutes, four times a week for six weeks. The control group received usual care. Main outcome measures: The feasibility of the intervention was assessed by recording exercise adherence and acceptability, exercise intensity, fatigue, muscle soreness and adverse events. The primary outcome measure of efficacy was walking capacity (6-minute walk test distance). Results: Home-based treadmill training was feasible, acceptable and safe with participants completing 78% (SD 36) of the prescribed training sessions. The treadmill training group did not improve their walking capacity compared to the control group. The treadmill training group showed a greater improvement than the control group in fatigue at post test (P = 0.04) and in quality of life at six weeks follow-up testing (P = 0.02). Conclusions: Semi-supervised home-based treadmill training is a feasible and safe form of exercise for cognitively intact people with mild Parkinsons disease. Further investigation regarding the effectiveness of home-based treadmill training is warranted.