Background. The presence of thrombus in the left atrial appendage (LAA) and/or LA body has so far been considered a contraindication to the transcatheter mitral valve (MV) in bioprosthetic MV/ MV annuloplasty ring implantation. Objective. The aim of this study is to describe, for the first time to our knowledge, the utilization of both two-dimensional (2D) and three-dimensional (3D) transesophageal echocardiography (TEE) in successfully performing without any embolic or other complications transcatheter MV in bioprosthetic MV/ mitral ring implantation using the apical approach in a group of 12 patients (pts) with co-existing LAA and/or LA body thrombus. Patients, Methods and Results. All pts were severely symptomatic with severe bioprosthetic MV stenosis in 9, severe native MV stenosis with a previous surgically inserted MV annuloplasty ring in 1 and severe MV regurgitation secondary to bioprosthetic cusp rupture in 2 pts. Thrombus in the LAA and/ or LA body was noted in all pts by 2D and 3DTEE. All pts were at high or prohibitive risk for surgery and all refused surgery. Utilizing both 2D and 3DTEE, especially 3DTEE, the guidewires and the prosthesis deployment system could be manipulated under direct vision through the MV bioprosthesis into the LA and left superior pulmonary vein bypassing and avoiding any contact with the thrombus. The transcatheter procedure was successfully accomplished in all patients with relief of stenosis/ regurgitation and amelioration of symptoms with no embolic or other complications during the procedure and over a mean follow-up period of 21 months. Conclusion. Our small study demonstrates the feasibility of successfully performing transcatheter MV in bioprosthetic MV/ MV annuloplasty ring procedure in pts with thrombus in LAA and/or LA body without any embolic or other complications.