Purpose: We evaluated the clinical significance of the tumor growth factor, midkine (MK), in paired gastric cancer and normal tissues. Materials and Methods: Twenty paired normal and cancer tissues were tested for MK mRNA expression by Northern blot analysis. Vessel staining was done by immunohistochemical staining using CD-31 monoclonal antibody (Dako). Results: MK mRNA was mainly expressed in cancer tissues (11 versus 1). Lymph node metastasis, pathological stage and tumor differentiation did not correlate with MK expression. However, MK expression rate increased with increment in tumor size (p=0.05). Microvascular density did not correlate with tumor invasion, lymph node metastasis, and pathological stages. However, there was a tendency of vascular density increment with MK expression in Tl-T2 stage. Conclusion: MK was mainly expressed in larger gastric cancer tissues suggesting its role in cancer growth in vivo. But no definite correlation between MK expression and tumor microvascular density was found.