The expression of CAIX is associated with poor prognosis in many solid malignancies; however, its role in breast cancer remains controversial.<h4>Methods</h4>The present study performed a meta-analysis to evaluate the correlation between CAIX expression and disease-free survival (DFS) and overall survival (OS) in breast cancer.<h4>Results</h4>A total of 2,120 publications from EMBASE, PubMed, Cochrane, and Scopus were screened. The gene discussed is CA9; the disease is breast cancer.