Summary Objective To examine the effectiveness of dance on motor functions, cognitive functions, and mental symptoms of Parkinson's disease (PD). Design This study employed a quasi-randomised, between-group design. Setting Dance, PD exercise, and all assessments were performed in community halls in different regions of Japan. Participants Forty-six mild-moderate PD patients participated. Intervention Six PD patient associations that agreed to participate in the study were randomly assigned to a dance group, PD exercise group, or non-intervention group. The dance and PD exercise groups performed one 60-min session per week for 12 weeks. Control group patients continued with their normal lives. All groups were assessed before and after the intervention. Main outcome measures We used the Timed Up-and-Go Test (TUG) and Berg Balance Scale (BBS) to assess motor function, the Frontal Assessment Battery at bedside (FAB) and Mental Rotation Task (MRT) to assess cognitive function, and the Apathy Scale (AS) and Self-rating Depression Scale (SDS) to assess mental symptoms of PD. The Unified Parkinson's Disease Rating Scale (UPDRS) was used for general assessment of PD. Results When comparing results before and after intervention, the dance group showed a large effect in TUG time (ES=0.65, p =0.006), TUG step number (ES=0.66, p =0.005), BBS (ES=0.75, p =0.001), FAB (ES=0.77, p =0.001), MRT response time (ES=0.79, p <0.001), AS (ES=0.78, p <0.001), SDS (ES=0.66, p =0.006) and UPDRS (ES=0.88, p <0.001). Conclusions Dance was effective in improving motor function, cognitive function, and mental symptoms in PD patients. General symptoms in PD also improved. Dance is an effective method for rehabilitation in PD patients.