Abstract: Objective: To detect the transcriptional expression of mitochondrial genome (mtDNA) in gastric cancer and matched normal gastric mucosa and to further discuss the role of NA transcripts in gastric carcinogenesis. Methods: Reversed-transcription PCR (RT-PCR) was applied to detect the transcripts of COⅠ, ND4, ND5, cyt-b and ATPase6 in 42 matched gastric cancers and normal mucosal tissues, meantime β-actin was served as a quantitative standard marker, followed by agarose gel electrophoresis. Results: Mitochondrial CO1 and ND4 transcripts in gastric cancers were higher than those in normal mucosal tissues, P<0.01. Transcriptional levels of mtDNA were negatively correlated with grades of histological differentiation of gastric cancers. ND4 and CO1 expression levels were higher in intestine type of gastric cancers than in diffused type, P<0.05. Conclusion: Gastric carcinogenesis needs elevated mitochondrial transcripts and proteins to provide tumor cells with energy and other materials to maintain its malignant biological phenotype and behavior.