miR-30a is situated on chromosome 6q.13 and is produced by an intronic transcriptional unit. However, its role in regulating the apoptosis, invasion and metastasis of breast cancer cells is not yet fully understood. The aim of this study was to research the biological function of miR‑30a and its direct target gene in breast cancer. The biological function of miR‑30a was determined by examining breast cancer cell growth, apoptosis, metastasis and invasion. In addition, Notch1 expression was measured by western blot analysis, and a luciferase reporter vector was constructed to identify the miR‑30a target gene. miR‑30a was found to be significantly downregulated in breast cancer cells. We also found that miR‑30a inhibited breast cancer cell viability, migration and invasion, and induced cell apoptosis. On the whole, our data indicate that miR‑30a attenuates the development of breast cancer by regulating the expression of the downstream target gene, Notch1.