BACKGROUND: Hepatocellular carcinoma [HCC] is a leading cause of cancer-related mortality worldwide, necessitating the exploration of novel therapeutic targets. Although accumulating studies have identified Ferredoxin 1 [FDX1], a key regulator of cuproptosis, as a candidate tumor suppressor and potential therapeutic target, its role and mechanism remain elusive in HCC. METHODS: The FDX1 expression was investigated in human HCC tissues and cell lines. Potential microRNAs targeting FDX1 were predicted by bioinformatic analysis and validated using qPCR screening, a dual luciferase reporter assay, MiR-3130-5p and miR-1910-3p mimics and inhibitors, overexpression plasmids, and xenograft nude mouse model. The correlation between miR-3130-5p/FDX1 axis and HCC patient prognosis was analyzed by using Kaplan-Meier survival analysis. RESULTS: We demonstrated that the expression of FDX1 was downregulated in human HCC tissues and cell lines compared to non-cancerous counterparts, and the downregulation of FDX1 was associated with poor overall survival in HCC patients. Subsequent bioinformatic analysis and experimental validations showed that FDX1 expression was reduced by microRNA [miR]-3130-5p mimic while induced by miR-3130-5p inhibitor. Further, miR-3130-5p was upregulated in HCC tissues and cells, correlating with a poor prognosis of HCC patients. Besides, lentivirus-mediated overexpression of miR-3130-5p significantly enhanced HCC growth in xenograft nude mouse models. Mechanistically, it was demonstrated that miR-3130-5p inhibited FDX1 expression via binding to its 3' untranslated region [3' UTR], while overexpression of FDX1 counteracted the promoting effect of miR-3130-5p on HCC cell proliferation. CONCLUSION: These findings suggest the miR-3130-5p/FDX1 axis as a prognostic biomarker as well as a potential therapeutic target in HCC.