Background/aim To assess sarcopenia and dynapenia and their relationship with disease severity and disabilities in PD and to state body composition in PD. Methods We conducted a case-control, cross-sectional study that included 70 patients with idiopathic PD and 85 controls. Sarcopenia was defined according to the European Working Group on Sarcopenia in Older People (EWGSOP) criteria. Dynapenia was detected by a handheld dynamometer. Bioimpedance analysis (BIA) was performed, and the SARC-F questionnaire was applied. Disabilities were appointed according to the Katz and Lawton indexes. Results Sarcopenia and dynapenia were more prevalent in PD than in controls (50 vs 30.6% and 31.4 vs 17.6%, respectively). Dynapenia was significantly associated with the severity of the disease and disabilities (p = 0.047, p = 0.001); however, sarcopenia was not. The skeletal muscle mass index (SMMI), fat mass index (FMI), and fat-free mass index (FFMI) did not differ between the PD and controls. FMI was lower in the advanced stages of the disease. Higher scores in the SARC-F questionnaire were significantly associated with disabilities and the severity of the disease (p < 0.001, p < 0.001). Conclusion Muscle strength was closely associated with the severity of the disease and disabilities in PD, but muscle mass was not. Sarcopenia, defined by the SARC-F questionnaire, was a good predictor of disabilities in PD, while the EWGSOP criteria were not. PD patients have a favorable body composition even in advanced stages of the disease with lower FMI and protected lean mass.