To establish the role of oxidative stress and v-akt murine thymoma viral oncogene homolog (AKT) activation in gastric cancer development, we examined the levels of phosphorylated AKT (pAKT), inducible nitric oxide synthase (iNOS), nitrotyrosine (NT), and human telomerase reverse transcriptase (hTERT) by enzyme-linked immunosorbent assay in 73 non-cancerous gastric mucosa and 10 gastric carcinomas. We found that the levels of pAKT were associated with the levels of iNOS, NT, and hTERT. Gastric mucosa was classified into four categories: chronic gastritis without Helicobacter pylori (CG), chronic active gastritis with H. pylori (CAG), chronic metaplastic gastritis without H. pylori (CMG), and chronic gastritis with atypia without H. pylori (CGA). We found increasing levels of pAKT, iNOS, and NT in the order of CG, CAG, CMG, and CGA. hTERT was detected only in CGA. These findings suggest that oxidative stress might be associated with AKT activation and hTERT induction and that mucosa in CGA might confer a high-risk status for gastric carcinogenesis.