Aim: Patients with chronic hepatitis C virus (HCV) infection who develop hepatocellular carcinoma (HCC) soon after treatment with direct antiviral agents (DAA) may have been harboring hitherto hidden tumors. If this were true, they should have a lower sustained viral response (SVR) rate, since active HCC hampers DAA efficacy. We aimed to verify this hypothesis. Methods: We included all patients who attended an HCV clinic, provided that they: (1) had no previous history of HCC; (2) had received at least one DAA dose; and (3) had been followed-up clinically and ultrasonographically for at least six months after concluding DAA. Results: The study population included n = 789 patients (55% males, median age 62 years). A median of 9.3 months (8.8-11.9) after concluding DAA, n = 19 (2.4%) patients were discovered to harbor HCC. In comparison to all others, patients with HCC were more commonly male (84% vs. 54%, P = 0.009), obese (47% vs. 17%, P = 0.002), and cirrhotic (95% vs. 35%, P < 0.001) and had less commonly achieved an SVR (68% vs. 98%, P < 0.001). Moreover, they had a trend for being less commonly treatment naïve (58% vs. 67%, P = 0.051). Based on multivariate analysis, the independent predictors of HCC were male sex (P = 0.031), cirrhosis (P = 0.004), obesity (P = 0.006), and failure to achieve an SVR (P < 0.001). Conclusion: Lack of achieving SVR is a strong independent predictor of development of HCC early after treatment of hepatitis C with DAA. Treatment failure should further alert clinicians to the possibility of this dreadful complication.