Background: A test to narrow down patients who require esophagogastroduodenoscopy (EGD) with a high probability of having gastroesophageal varices (GEV) and a high-risk of liver-related events is an unmet need. Methods: The measurement of serum fibrosis markers and EGD was performed in 166 consecutive chronic hepatitis C patients. The correlation between the grades of GEV and fibrosis markers and the subsequent occurrence of liver-related and fibrosis markers were examined. Results: Wisteria floribunda agglutinin-positive human Mac-2 binding protein (WFA⁺–M2BP) levels increased according to the grade of GEV (3.4 (0.2–18.6) for no GEV, 7.9 (1.8–20.0) for small GEV, and 11.4 (4.0–20.0) for large GEV; p < 0.001). The diagnostic accuracy of the WFA⁺–M2BP was superior compared to other serum fibrosis markers, and WFA⁺–M2BP was an independent predictor of GEV in the multivariate analysis. Furthermore, the cumulative incidence of liver-related events at one year was 2.3% in patients with WFA⁺–M2BP levels ≤ 7.0 and 37.5% in patients with WFA⁺–M2BP levels > 7.0 (p < 0.001). WFA⁺–M2BP > 7.0 was a significant predictive factor for liver-related events (Hazard ratio 6.7, p = 0.004) independent of Child–Pughclass. Conclusions: WFA⁺–M2BP could be used to estimate the presence and grade of GEV and is linked to liver-related events in chronic hepatitis C patients.