Although percutaneous transvenous mitral commissurotomy (PTMC) is now the preferred treatment modality for selected patients with mitral stenosis, there are certain settings where its application remains controversial or even contraindicated, mainly because of an increased risk of major complications. In this report, 3 such complex PTMC cases are described. A 39-year-old female with a rare combination of mitral stenosis and concomitant sizeable atrial septal aneurysm underwent a successful PTMC procedure. PTMC in a 60-year-old female with coexisting severe kyphoscoliosis which required major adjustments to the transseptal technique yielded an improvement in the mitral valve area from 1.0 cm2 to 1.9 cm2. In the third patient who was in her 25th week of gestation and had evidence of congestive cardiac failure, an abbreviated and expeditious PTMC procedure was carried out uneventfully. The 3 cases reported here highlight the feasibility, safety and efficacy of complex PTMC in the presence of atrial septal aneurysm, severe kyphoscollosis and pregnancy.