Abstract Background: Percutaneous mitral commissurotomy now has emerged as the treatment of choice for severe pliable rheumatic mitral stenosis with good immediate hemodynamic outcome, low complication rates, and clinical improvement. P-wave dispersion (PWD) is a noninvasive (ECG) marker for atrial remodeling and predictor for atrial fibrillation. Effect of PMC on risk of atrial fibrillation is not well studied. Aim of Study: To evaluate the effect of percutaneous mitral commissurotomy on P wave dispersion to assess the risk of atrial fibrillation. Patients and Methods: This study is a prospective study which was on 36 patients with significant mitral stenosis (MV Area less than 1.5cm2) presenting to Cardiology Department at Ain Shams University Hospital at 2022, all patients under-went PMC and ECG before PMC, 24 hours after PMC and two months after PMC. Results: The comparison of MVA, PWD and LA volume before, 24 hours postoperatively and at two months follow-up after PMC, showed that there was significant increase in MVA at 24 hours postoperatively from (0.87±0.2cm2) to (2.01 ±0.21cm2) p-value <0.001. P wave dispersion (PWD) showed significant decrease 24 hours after PMC from (63.33±11.71ms) to (51.39±9.23ms) after 24 hours and to (39.31±11.03ms) two months after PMC p-value <0.001. Also, left atrial volume (LA volume) showed significant decrease from (113.19±  21.6ml) to (102.22±21.87ml) 24 hours after PMC and to (88.75±21.04ml) two months after PMC p-value <0.001. P wave dispersion (PWD) decreased in 27 patients (75%) 24 hours after PMC and in 33 patients (91.7%) after two months after PMC among suited patients. Conclusion: Percutaneous mitral commissurotomy was safe and effective in the treatment of mitral stenosis, it was associated with significant reduction in P-wave dispersion and left atrial volume and increase in mitral valve area as well as reduced risk of atrial fibrillation.