Objective Although the effect of decitabine on myelodysplastic syndrome (MDS) has been demonstrated, merely a proportion of patients respond to therapy, and no well-recognized predictors have been identified. This study was conducted to investigate the effectiveness of decitabine in real-world clinical practice, and determine the predictive factors of response and overall survival (OS) in MDS patients. Methods Clinical and pathological data were collected from 94 patients and analyzed. These patients were reclassified according to the 2016 World Health Organization classification criteria, and restratified by International Prognostic Scoring System prognostic scores. The response evaluation was performed according to the 2006 modified International Working Group response criteria. Results In this study, 62% of patients responded to decitabine. Among these patients, 15 patients (16%) obtained complete remission (CR), 15 patients (16%) obtained marrow CR with hematologic improvement (HI), 20 patients (21%) obtained marrow CR without HI, and 8 patients (9%) only obtained HI, and no patient botained partial remission. The OS of the responders was significantly longer than that of non-responders (67 months vs. 7 months, P<0.001). The OS in patients with and without platelet doubling was significantly different in both the low/intermediate and high/very high risk groups (P=0.0398 and P=0.0330). The multivariate analysis revealed that platelet doubling after the first decitabine cycle is an independent predictor of response and OS in MDS patients (P=0.002 and P=0.008). Conclusion Decitabine is effective for treating MDS patients in real-world clinical practice. Furthermore, platelet doubling after the first decitabine cycle can be used as a predictor of response and survival in MDS patients.