Objective To systematically evaluate the effectiveness of dasatinib in doses of 140 mg once daily and 70 mg twice daily for chronic myeloid leukemia (CML). Methods The randomized controlled trials (RCTs) were retrieved from Embase (1974 to November 2011), Pubmed (1966 to November 2011), The Cochrane Library (Issue 11, 2011), CBM (1979 to November 2011), VIP (1989 to November 2011), CNKI (1994 to November 2011), Wanfang Data (1997 to November 2011) and references listed in all articles. RCTs meeting inclusive criteria were included, the data were extracted, the quality was evaluated and cross-checked by two reviewers independently according to Cochrane Handbook for Systematic Reviews of Interventions, and then meta-analyses were conducted using RevMan 5.1 software. Results A total of four studies involving two RCTs and 862 patients were included. Results of meta-analyses showed that when dasatinib was used in the long-term treatment of CML, no significant difference was found between 140 mg once daily and 70 mg twice daily in the complete hematologic response (RR=0.97, 95%CI 0.88 to 1.07, P=0.58), complete cytogenetic response (RR=0.94, 95%CI 0.80 to 1.11, P=0.47) and major cytogenetic response (RR=0.99, 95%CI 0.86 to 1.13, P=0.86). In the short-term treatment of CML, there were no significant differences in the complete hematologic response (RR=0.99, 95%CI 0.90 to 1.07, P=0.73), complete cytogenetic response (RR=0.99, 95%CI 0.78 to 1.26, P=0.95) and major cytogenetic response (RR=1.01, 95%CI 0.83 to 1.22, P=0.95). The subgroup analyses on the long-term treatment of CML in both chronic phase and advanced phase showed that there were no significant differences in the complete hematologic response, major cytogenetic response and complete cytogenetic response. Conclusion In the effectiveness of dasatinib for CML, the dose of 140 mg once daily is similar to the dose of 70 mg twice daily. Considering possible moderate selection bias existing in the methodological quality of the included studies which may affect the authenticity of outcomes, this conclusion should be further proved by conducting more high-quality, large-scale and double- blinded RCTs.