Background: High-sensitivity C-reactive protein (hs-CRP) is a sensitive systemic marker of inflammation, and increased levels of hs-CRP are associated with inflammatory reactions. Microglia-mediated neuroinflammation has been hypothesized to play an important role in the pathogenesis of idiopathic Parkinson’s disease (PD). However, the clinical value of hs-CRP in PD is poorly defined. Therefore, we conducted this study to investigate the clinical value of hs-CRP in patients with PD. Methods: We examined 212 patients with de novo PD, 253 patients with acute ischemic cerebrovascular disease and 119 healthy subjects and investigated the differences in hs-CRP among these 3 groups. The PD group was classified into 4 subgroups according to the Hoehn and Yahr stage to investigate the relationship between hs-CRP and symptom severity. Results: There was no significant difference in the hs-CRP value between the PD and the ischemic cerebrovascular disease groups, but the subjects in the 2 disease groups demonstrated higher hs-CRP levels than those in the normal control group. A post-hoc analysis of the 4 PD subgroups showed no significant differences in hs-CRP values. In addition, this study demonstrated that the odds ratio of the PD group by hs-CRP was 2.037 (95% CI 1.180–3.517; p = 0.011). Conclusion: We suggest that our results could support the hypothesis that neuroinflammation contributed to the pathogenesis of PD and cautiously assume that elevated hs-CRP might have a clinical value as a risk factor for PD.