Aims: We aimed to derive a model to discriminate cirrhotic patients with poor prognosis even if the Model for End Stage Liver Disease (MELD) score is low. Methods: This study enrolled 700 cirrhotic patients with MELD score of less than 20 who underwent hepatic vein pressure gradient (HVPG) measurement. A novel model using HVPG to predict overall survival was derived and specified as the H6C score. Internal and external validations were conducted with the derivation and validation cohorts. Results: The H6C score using the HVPG and Child-Pugh scores was developed on the basis of a multivariate Cox regression analysis. The H6C score showed great predictive power for overall survival with a time-dependent AUC of 0.733, which was superior to that of a MELD of 0.602. In patients with viral etiology, the performance of the H6C score was much improved with a time-dependent AUC of 0.850 and was consistently superior to that of the MELD (0.748). Patients with an H6C score below 45 demonstrated an excellent overall survival with a 5-year survival rate of 91.5%. Whereas patients with an H6C score above 64 showed a dismal prognosis with a 5-year survival rate of 51.1%. The performance of the H6C score was further verified to be excellent in the validation cohort. Conclusions: This new model using the HVPG provides better predictive power than the MELD in cirrhotic patients, especially with viral etiology. In patients with H6C above 64, it would be wise to consider early liver transplantation in order to positively impact long-term survival, even when these patients have a low MELD score.