Recurrence of hepatitis C after liver transplantation (LT) is the main cause of graft loss and retransplantation. Frequent liver biopsies are essential to follow-up hepatitis C virus (HCV)–induced liver damage. However, liver biopsy is an invasive and expensive procedure. We evaluated prospectively the diagnostic accuracy of noninvasive measurement of liver stiffness (by transient elastography) to assess the severity of hepatitis C recurrence after LT. For this purpose, we included 124 HCV-infected liver transplant recipients who underwent 169 liver biopsies and 129 hepatic hemodynamic studies with determination of hepatic venous pressure gradient (HVPG). Simultaneously, patients underwent measurement of liver stiffness. Liver fibrosis was mild (F0-F1) in 96 cases (57%) and significant (F2-F4) in 73 (43%). HVPG was normal (<6 mm Hg) in 69 cases (54%) and elevated (≥6 mm Hg) in 60 (46%). Using a liver stiffness cutoff value of 8.5 kilopascals, the sensitivity, specificity, negative predictive value, and positive predictive value for diagnosis of fibrosis ≥F2 were 90%, 81%, 79%, and 92%, respectively. The area under the curve (AUC) for diagnosis of fibrosis ≥F2, ≥F3 and F4 were 0.90, 0.93, and 0.98, respectively. There was a close direct correlation between liver stiffness and HVPG (Pearson coefficient, 0.84; P < 0.001) and the AUC for diagnosis of portal hypertension (HVPG ≥6 mm Hg) was 0.93. Importantly, none of the individuals with liver stiffness below the cutoff value had either bridging fibrosis (F3) or cirrhosis (F4) or significant portal hypertension (HVPG ≥10 mm Hg). In conclusion, determination of liver stiffness is an extremely valuable tool to assess the severity of HCV recurrence after LT and in reducing the need of follow-up liver biopsies. Liver Transpl 12:1791-1798, 2006. © 2006 AASLD.