Introduction: Voltage-gated sodium (Nav) channels encoded by SCNs are heteromeric protein complexes containing pore-forming α subunits together with non-pore-forming β subunits. Methods: To analyze the expression of SCNs in the samples of different types of breast cancer (BC) patients and the relationship between the expression of α and β subunits and the prognosis of in BC patients, the study investigated the roles of SCNs in the prognosis of BC using ONCOMINE, UALCAN, Kaplan-Meier Plotter, GEPIA, Metascape, LinkedOmics databases. The study analyzed significant changes of SCNs expression and prognosis in transcription level between BC and normal samples, and association of mRNA expression of distinct SCNs family members with prognosis in overall BC patients and HER2-positive/HER2-negative subgroups, respectively. Moreover, we predicted functions and pathways of the mutations in SCNs and their neighbor genes in BC patients by GO/KEGG and GSEA analysis. Results: The results showed that transcriptional and proteinic expressions of 9 SCNs were downregulated in patients with BC, including SCN1A~4A, 7A, 9A and SCN2B~4B. low expressions of 11 SCNs members were found to be significantly associated with poorer overall survival (OS) in BC patients (P＜0.01), including SCN2A, 3A, 5A, 7A, 9A~11A and SCN1B~4B. Moreover, prognostic value of mRNA expression of SCNs could only be seen in HER2-negative BC patients when we performed subgroup analysis. Conclusions: These results indicated that SCNs could be prognostic biomarkers for survivals of BC patients. Some medicines that regulate SCNs might provide new targets for BC treatment.