AbstractPeople with Parkinson's disease (PD) often have a posture characterized by lateral trunk flexion poorly responsive to antiparkinsonian drugs. To examine the effects of a rehabilitation programme (daily individual 90‐minute‐sessions, 5‐days‐a‐week for 4‐consecutive weeks) on lateral trunk flexion and mobility, 22 PD patients with mild to severe lateral trunk flexion, and 22 PD patients without trunk flexion were studied. Patients were evaluated using the Unified Parkinson's Disease Rating Scale motor subscale (UPDRS‐III) score, and the kinematic behavior of the trunk was recorded by means of an optoelectronic system to determine: a) trunk flexion, inclination and rotation values in the erect standing posture; b) ranges of trunk flexion and inclination during trunk movements. After the treatment, significant decreases in trunk flexion [24°(4) vs. 14°(3), P < 0.001] and inclination in the static condition [23°(5) vs. 12°(4), P < 0.001)] were observed, both of which were maintained at the 6‐month follow up. During the trunk flexion task, a significantly increased range of trunk flexion [64°(15) vs. 83°(15), P < 0.001] was observed; similarly, during the lateral bending task, the range of trunk inclination was found to be significantly increased, both toward the side of the trunk deviation [29°(8) vs. 42°(13), P < 0.01] and toward the contralateral side [14°(6) vs 29°(11), P < 0.01]. No further significant changes were observed at the 6‐month follow‐up. Trunk flexion and inclination values in the upright standing posture correlated slightly with the UPDRS‐III score. Our findings show that significant improvements in axial posture and trunk mobility can be obtained through the 4‐week rehabilitation programme described, with a parallel improvement in clinical status. © 2010 Movement Disorder Society