One of the treatment options in mitral stenosis (MS) is balloon mitral valvulotomy (BMV) which may improve myocardial intrinsic function. This study was aimed to observe myocardial systolic function with intrinsic parameter by using STDS- focusing on global longitudinal strain (GLS) - in MS pre and post BMV. This descriptive analytic study which included MS patients who underwent BMV from 2009-2011, were examined by routine echocardiography examination, one day pre BMV and maximal 5 days post BMV. STDS of 4 Left ventricle chambers were taken. Exclusion criteria were: post BMV gradient more than 10 mmHg and post BMV significant mitral regurgitation. Paired t-test analysis was used to compare variables pre and post BMV procedure. There were 45 MS patients with mean age of 39 years old (± 10.7), pre BMV: mean MVA 0.68 cm2 (SD 0.57), mean MVG 14.02 mmHg (SD 5.06), mean EF 58.26% (SD 8.82) and mean GLS -11.81 (SD 3.50). Post BMV: mean MVA 1.4 cm2 (p : 0.000), mean MVG 5.82 (p<0.001), mean EF 61.28% (p=0.001) and GLS also significantly improved to 13.18 (p=0.02). Improvement of LVMIF after BMV procedure, may explain beneficial effect of BMV in regional myocardial deformation and systolic function in MS patients.