Matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in peripheral blood were measured in 54 patients with gastric carcinoma; 46 were primary and 8 were recurrent cases. There were no significant associations between MMP-9 concentrations and clinicopathological factors. TIMP-1 levels were significantly increased in advanced and recurrent cases, and in cases with peritoneal dissemination and lymph node metastasis, suggesting that TIMP-1 concentration in the peripheral blood could be a new tumor marker for the recurrence of gastric carcinoma.