Percutaneous mitral balloon valvotomy (PMV) was performed successfully in a 41-year-old pregnant patient with severe mitral stenosis. The patient had a 21-week gestation and was severely limited by symptoms resulting from critical mitral stenosis. PMV resulted in a decrease in the diastolic mitral gradient from 26 to 2 mm Hg and an increase in both cardiac output (from 4.2 to 5.7 l/min) and mitral valve area (from 0.7 to 3.7 cm2). She had marked symptomatic improvement, no further heart failure, and a full-term, normal delivery. This case report indicates that PMV may be the treatment of choice in the management of pregnant patients with incapacitating symptoms caused by severe mitral stenosis.