Background: The use of adjunct rasagiline in levodopa-treated patients with Parkinson's disease and motor fluctuations is supported by findings from large-scale clinical studies. This study is to investigate the efficacy and safety of adjunct rasagiline in Chinese patients with Parkinson's disease, as a product registration study. Methods: This 16-week, randomized, double-blind, parallel-group, multicenter, placebo-controlled study of rasagiline 1 mg/day included levodopa-treated patients with Parkinson's disease and motor fluctuations. The primary efficacy endpoint was mean change from baseline in total daily OFF time over 16 weeks. Secondary endpoints were Clinical Global Impressions - Improvement (CGI-I), and change in Unified Parkinson's Disease Rating Scale (UPDRS) Activities of daily living (ADL) and Motor scores. Patient well-being (EQ-5D), and the frequency of adverse events were also assessed. Results: In total, 324 levodopa-treated patients were randomized to rasagiline 1 mg/day (n = 165) or placebo (n = 159). Over 16 weeks, rasagiline statistically significantly reduced the mean [95% confidence interval] total daily OFF time versus placebo (-0.5 h [-0.92, -0.07]; p = 0.023). There were also statistically significant improvements versus placebo in CGI-I (-0.4 points [-0.61, -0.22]; p < 0.001), UPDRS-ADL OFF (-1.0 points [-1.75, -0.27]; p = 0.008), and UPDRS-Motor ON (-1.6 points [-3.05, -0.14]; p = 0.032) scores, as well as the EQ-5D utility index (p < 0.05). Rasagiline was safe and well tolerated. Conclusions: In levodopa-treated Chinese patients with Parkinson's disease and motor fluctuations, adjunct rasagiline 1 mg/day statistically significantly reduced OFF time, and improved daily function and overall well-being, versus placebo. Consistent with findings in other countries, adjunct rasagiline was proven efficacious and well tolerated in Chinese patients.