Introduction: This study investigated the combination of venous stasis and inflammation in varicose vein development. Methods: The study included patients with primary varicose veins operated using high ligation and stripping of greater saphenous vein. All of them showed reflux at sapheno-femoral junction on preoperative Doppler ultrasound. Mesenteric veins from early or advanced gastric cancer specimens were used as control group. Inflammatory mediators expressed in the venous wall were measured via immunohistochemistry and compared between the two groups. Results: Thirty-five (59.3%) men and 24 women with a mean age of 52.8 years (range, 23–77 years) were included and 29 (49.2%) patients had edema or skin changes according to Clinical-Etiology-Anatomy-Pathophysiology (CEAP) classification and reporting standards for chronic venous disorders. The expression of interleukin 6 (IL-6) and transforming growth factor β1 (TGF-β1) in intima and those of IL-6 in media of greater saphenous veins increased, with statistically significant differences between the two groups (p < 0.001). IL-6 in media and TGF-β1 levels in intima were independent predictors of varicose veins (adjusted odds ratios 74.62 and 66.69, respectively). Conclusion: Elevated venous pressure represented by reflux on Doppler ultrasound and increased expression of inflammatory cytokines including IL-6 in media and TGF-β1 in intima are associated with the development of varicose veins.