Background:　Although　esophageal　carcinoma　(EC)　is　one　of　the　most　common　cancers　in　the　world,　details　of　its　pathogenesis　remain　unclear.　Metabolic　reprogramming　is　a　main　feature　of　EC.　Mitochondrial　dysfunction,　especially　the　decrease　in　mitochondrial　complex　I　(MTCI),　plays　an　important　role　in　the　occurrence　and　development　of　EC.　Objective:　The　objective　of　the　study　was　to　analyze　and　validate　the　metabolic　abnormalities　and　the　role　of　MTCI　in　esophageal　squamous　cell　carcinoma.　Methods:　In　this　work,　we　collected　transcriptomic　data　from　160　esophageal　squamous　carcinoma　samples　and　11　normal　tissue　samples　from　The　Cancer　Genome　Atlas　(TCGA).　The　OmicsBean　and　GEPIA2　were　used　to　conduct　an　analysis　of　differential　gene　expression　and　survival　in　clinical　samples.　Rotenone　was　used　to　inhibit　the　MTCI　activity.　Subsequently,　we　detected　lactate　production,　glucose　uptake,　and　ATP　production.　Results:　A　total　of　1710　genes　were　identified　as　being　significantly　differentially　expressed.　The　Kyoto　Encyclopedia　of　Genes　and　Genomes　(KEGG)　and　Gene　Ontology　(GO)　enrichment　analysis　suggested　that　these　differentially　expressed　genes　(DEGs)　were　significantly　enriched　in　various　pathways　related　to　carcinoma　tumorigenesis　and　progression.　Moreover,　we　further　identified　abnormalities　in　metabolic　pathways,　in　particular,　the　significantly　low　expression　of　multiple　subunits　of　MTCI　genes　(ND1,　ND2,　ND3,　ND4,　ND4L,　ND5,　and　ND6).　Rotenone　was　used　to　inhibit　the　MTCI　activity　of　EC109　cells,　and　it　was　found　that　the　decrease　in　MTCI　activity　pro-moted　HIF1A　expression,　glucose　consumption,　lactate　production,　ATP　production,　and　cell　migration.　Conclusion:　Our　results　indicated　the　occurrence　of　abnormal　metabolism　involving　decreased　mi-tochondrial　complex　I　activity　and　increased　glycolysis　in　esophageal　squamous　cell　carcinoma　(ESCC),　which　might　be　related　to　its　development　and　degree　of　malignancy.　©　2024　Bentham　Science　Publishers.