In the last decade, multiple studies depicted discrepancies between mitral valvular orifice area(MVA) measurements obtained with the pressure half-time(PHT) method and invasive methods during the immediate post-percutaneous mitral valvuloplasty(PMV) period. Our aim was to assess the accuracy of Real-Time 3D echo(RT3D) to measure the MVA in the immediate post-PMV period. The invasively determined MVA was used as the gold standard. We studied 29 patients with rheumatic mitral stenosis from two centres(27 women; mean age 48.2±11.3 years), all of which had underwent PMV. MVA was calculated before and after PMV using the PHT method, 2D echo planime try, RT3D echo planimetry and invasive determination (Gorlin’s method). The RT3D MVA assessment showed a better agreement with the invasively derived MVA before and in the immediate post-PMV period (Bland-Altman analysis: Average difference between both methods and limits of agreement: 0.01(-0.31 to 0.33) cm2 and -0.12(-0.71 to 0.47) cm2) before and immediately after the PMV, respectively. RT3D is a feasible and accurate technique for measuring MVA in patients with RMVS. It has the best agreement with the invasively determined MVA, particularly in the immediate post-PMV period. In the last decade, multiple studies of discrepancies between mitral valvular orifice area (MVA) measurements obtained with the pressure half-time (PHT) method and invasive methods during the immediate post-percutaneous mitral valvuloplasty (PMV) period. Our aim was to assess the accuracy of Real-Time 3D echo (RT3D) to measure the MVA in the immediate post-PMV period. The investigatedively determined MVA was used as the gold standard. We studied 29 patients with rheumatic mitral stenosis from two centers (27 women; mean age 48.2 ± 11.3 years), all of which had underwent PMV. MVA was calculated before and after PMV using the PHT method, 2D echo planime try, RT3D echo planimetry and invasive determination (Gorlin’s method). The RT3D MVA assessment showed a better agreement with the invasively derived MVA before and in the immediate post-PMV period (Bland-Altman analysis: Average difference between both methods and limits of agreement: 0.01 (-0.31 to 0.33) cm2 and -0.12 (-0.71 to 0.47) cm2) before and immediately after the PMV, respectively. RT3D is a feasible and accurate technique for measuring MVA in patients with RMVS. It has the best agreement with the invasively determined MVA, particularly in the immediate post-PMV period.