Background & Aims: Carvedilol is a non-selective β-blocker (NSBBs) with anti-α1-adrenergic activity, more effective than traditional NSBBs in reducing portal-pressure (HVPG). However, 35%-45% of patients still have insufficient HVPG-decrease. Statins ameliorate endothelial dysfunction, reduce hepatic vascular resistance, and have pleiotropic effects. We investigated whether the addition of simvastatin improves the efficacy of carvedilol on HVPG in cirrhosis with severe portal-hypertension and suboptimal response to traditional-NSBBs. Methods: Patients with cirrhosis and high-risk varices referred for primary prophylaxis were consecutively included. HVPG was measured at baseline and again after i.v.propranolol. Suboptimal responders (HVPG-decrease <20%) were treated with carvedilol and were randomized to double-blind administration of placebo or simvastatin. Chronic HVPG response was assessed after 4-6-weeks, repeating HVPG-measurements after a standard liquid meal to estimate endothelial dysfunction. Plasma samples were obtained before each study to investigate inflammatory parameters. Results: Of 184 eligible patients, 82 were randomized to carvedilol+simvastatin (N=41) or carvedilol+placebo (N=41). Baseline characteristics were similar. HVPG significantly decreased with both, carvedilol+simvastatin (18.6±4-to-15.7±4 mm Hg, p<0.001) and carvedilol+placebo (18.9±3-to-16.9±3 mm Hg, p<0.001). The decrease was greater with carvedilol+simvastatin (2.97±2.5 vs. 2.05±1.6 mm Hg, p=0.031). An HVPG-decrease ≥20% occurred in 37% versus 15% patients respectively (OR:3.37, 95% CI=1.15-9.85; p=0.021). With test-meal, HVPG increased in both groups (p<0.01), although carvedilol+simvastatin attenuated such increment (12±8% vs. 23±16%, p<0.001). Cytokine levels (IL-6,MCP-1,MDA) decreased significantly more with carvedilol+simvastatin (p<0.01). Incidence of adverse events was similar. Conclusion: In patients with severe portal hypertension (all with high-risk varices) and suboptimal hemodynamic response to traditional NSBBs, combined therapy with carvedilol plus simvastatin significantly enhances the portal-pressure reduction achieved with carvedilol-monotherapy, improves endothelial dysfunction and reduces pro-inflammatory cytokines.