Abstract Background Myocarditis is an inflammatory disease of the myocardium with multiple causes and evolutions. The aim of our study was to design a prognostic multiparametric score in patients with myocarditis, to identify those at higher risk of adverse cardiovascular events (AE). Methods A prospective study was performed enrolling 98 patients with myocarditis: 72 M, 26 F; median age 27 [IQR 20–40]. Patients were divided into 2 groups: complicated (CM) and uncomplicated myocarditis (UM). Six months after hospital admission, cardiac magnetic resonance (CMR) and cardiological consultation were repeated. AE (death, hospitalization for heart failure, heart transplant, ICD implantation, heart failure development) were evaluated at 6 months and after 3 years. Results We found 67 UM and 31 CM. AE were significantly higher in patients with complicated myocarditis. We found a significant correlation between AE and reduced left ventricular ejection fraction (LVEF) at hospital admission, increased GLS, septal LGE at CMR, longer persistence time of increased troponin, LGE extension progression or persistence 6-month CMR. A myocarditis prognostic score was developed on the basis of these parameters. A score ≥ 5 showed higher sensitivity (100%) and specificity (87%) - AUC 1, to identify AE in patients with myocarditis. A score between 3 and 4 showed high sensitivity but low specificity. A score ≤ 2 was associated with low probability of events. Conclusion Our study confirms the high probability of AE in patients with CM and it suggests a myocarditis prognostic score to identify patients at higher risk of AE.