OBJECTIVES To evaluate the safety and efficacy of balloon mitral valvotomy (BMV) in symptomatic rheumatic mitral stenosis (MS) patients with left atrial (LA) thrombus and to address the technical issues. BACKGROUND LA thrombus in patients with MS has long been regarded as a contraindication for BMV. There are few reports of BMV in presence of LA appendage (LAA) thrombus and reports of BMV in presence of LA body thrombus are still rare. METHODS 2,763 patients with suitable valve morphology were screened for BMV. 194 patients had LA/LAA thrombus and were put on adequate anticoagulation for 8-12 weeks. A total of 108 patients with persistent LA thrombus who satisfied the inclusion criteria (LA thrombus type Ia, Ib, and IIa) formed the study group and the remaining 2,622 patients who did not have any LA thrombus constituted the control group. All patients in the study group underwent BMV by modified over the wire technique. RESULTS There was significant and comparable improvement in the mitral valve area, mitral valve gradient, LA mean and pulmonary artery systolic pressure following the procedure in both groups. In the study group, there were no thromboembolic episodes during the procedure. However, there was one case of transient ischemic attack in the study group which occurred 6 hr after a successful BMV. In the study group, one patient had cardiac tamponade needing aspiration and there was no in-hospital death. CONCLUSIONS In selected patients of mitral stenosis with LA thrombus (type Ia, Ib, and IIa), BMV can be performed safely with the modified over the wire technique. Systemic thromboembolism, technical failures and other complications are very rare when performed by experienced operators.