Aim: The interleukin-6 (IL-6) pathway is one of the mechanisms that link inflammation and angiogenesis. The purpose of this study was to investigate the preoperative serum levels of IL-6 in gastric carcinoma with lymph node metastasis, and to correlate them with disease status. Method: A total of 100 patients who underwent gastrectomy were enrolled in this study. Serum levels of IL-6 were assessed enzyme linked immunosorbent assay (ELISA). Histological findings included tumor size, depth of tumor invasion, lymph node (LN) metastasis, and TNM stage. Result:Increases in cancer invasion and staging are generally associated with increases in preoperative serum IL-6 levels. IL-6 levels were correlated with invasion depth (p<0.001), LN metastasis (p<0.001), and TNM stage. The presence of peritoneal seeding metastasis is associated with IL-6 levels (p<0.001). Conclusion: Preoperative serum IL-6 levels might be markers of tumor invasion, LN metastasis, and TNM stage. These results suggest that IL-6 levels are potential molecular markers that predict lymphatic involvement in gastric carcinoma.