To test the hypothesis that plasminogen activator inhibitor-1 (PAI-1) may serve as a candidate marker for the malignancy of gastric cancer, we carried out quantitative reverse transcription–polymerase chain reaction for the PAI-1 gene and evaluated the possible relationship between PAI-1 gene expression levels and clinicopathological findings in gastric cancer. A significant increase in PAI-1 expression scores was observed in lymph node metastasis-positive gastric cancers (2.11 ± 0.35) compared to metastasis-negative cancers (0.33 ± 0.49) (P = 0.0048), as well as in distant metastasis-positive gastric cancers (3.68 ± 0.58) compared to metastasis-negative cancers (1.20 ± 0.32). The PAI-1 expression score markedly increased with tumor stage (P < 0.0001; ANOVA test). Moreover, multivariate analysis revealed the PAI-1 expression score to be a strong and independent prognostic factor for gastric cancer (P = 0.0450). These results suggested that PAI-1 might serve as a new and promising parameter for the prediction of prognosis in gastric cancer.