Background and purpose: Recent foreign studies have shown that GATA3 as a transcription factor is not only associated with the development of normal breast tissue and breast cancer, but also may be related to the prognosis of breast cancer. The aim of this study was to investigate the significance of GATA3 in breast cancer prognosis by detecting the expression level of GATA3 in breast cancer and analyzing its relationship with prognosis. METHODS: Immunohistochemical methods were used to detect the expression level of GATA3 in 100 breast cancers and analyze its relationship with other clinicopathological indicators and prognosis. RESULTS: Low GATA3 expression was associated with high tissue grade, lymph node metastasis, ER-negative status, PR-negative status, HER2 overexpression and other indicators indicating poor prognosis (P0.05); the 5-year overall survival rate was 83.6% in all breast cancer patients with positive GATA3 expression, which was higher than 62.2% in those with negative GATA3 expression, and there was a statistical difference between them.