Background Individuals with Parkinson's disease (PD), in addition to motor impairment, may evolve with respiratory and autonomic nervous system disorders. Currently, there are few studies with emphasis on muscle and pulmonary dysfunction and that verify the benefits of inspiratory muscle training (IMT) in this population. Aim The aim of this study was to evaluate whether IMT is effective for the improvement of respiratory muscle strength, lung function, thoracic mobility, functional capacity and cardiac autonomic function in PD. Methods A randomized and controlled trial will be conducted with 26 participants with idiopathic PD, with aged between 50 and 65 years, in the Stages I to III by the Modified Hoehn and Yahr Scale. Respiratory muscle strength will be performed by manovacuometry and lung function by spirometry. Functional capacity will be evaluated by the 6‐min walk test and autonomic cardiac function by heart rate variability. In addition, thoracic mobility measurement will also be performed. After the evaluations, these participants will be randomly assigned to two groups: the IMT group with Powerbreathe®, which will perform the eight series of 2 min each, with 1 min of rest between them, totaling 30 min, at 60% of the maximum inspiratory pressure and the control group, who will perform the same training protocol but with the load maintained at 9 cmH2O. All participants will be submitted to the same motor training protocol. Conclusion It is expected that IMT increases the inspiratory muscle strength, contributing to the improved expiratory muscle strength, lung function, thoracic mobility, functional capacity and cardiac autonomic function in individuals with mild to moderate PD.