Posture, gait and balance problems are very disabling symptoms in Parkinson's disease (PD). An increased stride-to-stri de variability, reduction of automaticity and asymmetry of lower limbs function characterize parkinsonian gait. These features predispose to freezing of gait (FOG), which often leads to falls. The aim of this study was to evaluate how the modulation of asymmetry through physiotherapy might improve gait and reduce FOG, thus preventing falls. Twenty-eight PD patients entered a double-blind pilot feasibility controlled study and were evaluated at baseline and after 3 months of a rehabilitative program (performed twice a week) by means of the motor part of the Unified Parkinson's Disease Rating Scale (UPDRS-III), Gait and Falls Questionnaire, Tinetti balance and gait scale, Short Physical Performance Battery (SPPB), European Quality of Life questionnaire. Patients were randomly assigned to three treatment arms: (1) worst side improvement; (2) best side improvement; (3) standard therapy. All study arms showed a significant improvement of the Tinetti and SPPB scores. BSI led to a greater improvement than ST in terms of UPDRS-III (p = 0.01); Tinetti total score (p = 0.05) and Tinetti gait subscore (p = 0.01). Our study confirms the efficacy of physical therapy in the treatment of PD and, more importantly, suggests that specific intervention tailored on individual feature (e.g., asymmetry of motor condition) might be even more effective than standard rehabilitative programs.