Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a major cause of life-threatening arrhythmias in young athletes. However in highly trained athletes the diagnosis is challenging because of overlapping features such as elevated right ventricular end-diastolic volume index (RVEDVi), furthermore revised Task Force criteria (TFC) contains no cut-off value for elit athletes. Our goal was to determine cardiac magnetic resonance (CMR) parameters and gender- specific cut-off values which can help differentiate ARVC from athlete’s heart. Between 2010 and 2016 we performed 522 CMR scans with the suspicion of ARVC. In 45 pts (38±10y,30 male) ECG abnormalities, family history, histology and/or CMR parameters fulfilled revised TFC. Additionally 80 elite athletes (26±4y,50 m, members of the Hungarian Olympic team) were examined by CMR. RVEDVi, ejection fraction (RVEF) and calculated derived parameters (LVEDV/RVEDV, LVEF/RVEF) were compared. Area under the curve (AUC) were analysed, optimal gender specific cut-off values were established from receiver operating characteristic (ROC) curves. There was no significant difference between RVEDVi of ARVC pts and athletes (m:129.2 vs 129.8, f:125.4 vs 110.7ml/m2). RVEF was lower in ARVC pts compared to athletes (m:46 vs 55.7, f:44.2 vs 58.4% p<0.001). In both gender, AUC of RVEF, LVEF/RVEF and LVEDV/RVEDV help distinguishing ARVC andathletes heart (p<0.01), but RVEDVi can not (p=NS). Male cut-off value for ratio of RVEF less than 48.2%, LV/RVEF more than 1.145 discriminated between athlete’s heart and ARVC with a sensitivity of 53% and a specificity of 100%. In females RVEF<51%, LV/RVEF>1.157 and LVEDV/RVEDV<0.915 discriminated ARVC and athletes heart with a sensitivity of 67%, 66% and 87%, specificity of 93%, 97% and 90%, respectively. Consequently, in highly trained healthy athletes RVEDVi is in the range of major TFC, while RVEF, LV/RVEDV and LV/RVEF could be useful parameters in differential diagnosis.