A 35-year-old female with twin gestation diagnosed with severe mitral stenosis and pulmonary hypertension was successfully treated with open heart surgery for mitral valve replacement (MVR). She gave birth to twins with good Apgar scores at 33 weeks of gestation by cesarean section. Cardiac surgery in singleton pregnancy has been reported extensively. However, there is only a single reported case of MVR following therapeutic abortion of a twin pregnancy in the second trimester. In contrast, we report the first case of mitral valve replacement for severe mitral stenosis and pulmonary hypertension in an ongoing twin pregnancy with successful outcomes.