OBJECTIVES: This study aimed to systematically review cost-effectiveness data of trastuzumab as an adjuvant treatment for early breast cancer in Asia. METHODS: Literature search, which ended on February 2018, was performed using five electronic databases (i.e. PubMed, SCOPUS, COCHRANE, CRD and Web of Science). Studies were identified by two independent reviewers in accordance to inclusion and exclusion criteria. References of the included studies were also screened for other relevant reports, with restriction to English language. Relevant data were extracted and assessed for risk of bias. The quality of each study was assessed using the checklist proposed by the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) Statement, Drummond and Philips checklists. To compare different currencies that have been used in the studies, all costs were converted to US dollars (US$) 2018. RESULTS: Six out of 250 studies identified met the inclusion criteria. Five were cost-effectiveness analysis (CEA) and one was cost-benefit analysis (CBA). The majority of the economic analyses were performed from the healthcare provider perspective. All CEA, except one Iranian study, obtained effectiveness data from HERA trial. For the quality assessment, all studies fulfilled more than 50% of the requirements in the CHEERS, Drummond and Phillips checklists. The incremental cost-effectiveness ratio (ICER) for evaluations performed for a time horizon of 20 years was US$51,863/QALY while studies that applied lifetime horizon reported an ICER of between US$7,676 /QALY to 22,664.75 /QALY. The model outcome was generally sensitive to changes in cost of trastuzumab, discount rate and duration of trastuzumab. CONCLUSIONS: One-year treatment of adjuvant trastuzumab for patients with early breast cancer in the Asian countries was found to be cost-effective.