Infective endocarditis is a rare complication of hypertrophic cardiomyopathy. It's estimated incidence is 1.4 per 1000 person/year in all patients and it increases to 3.8 per 1000 person/year in patients with left ventricular outflow obstruction. The most common site of vegetation is the ventricular aspect of anterior mitral valve leaflet. We report a case of a 43-year-old man who was admitted for mitral infective endocarditis resulting in severe mitral regurgitation complicating a hypertrophic obstructive cardiomyopathy. The patient underwent mitral valve replacement. Post-operative outcome was good with relieve of symptom and resolution of left ventricular outflow obstruction. Literature data are reviewed.