Forty-six children, aged 2 days to 16 years (median 2.4 years) with double orifice mitral valve (DOMV), were studied. Partial atrioventricular septal defect was the most commonly associated cardiac lesion. Symptoms were related to the degree of mitral insufficiency and/or stenosis when present. Surgical intervention directed at DOMV was required in the minority of patients who underwent repair of associated cardiac lesions. The long-term morbidity attributable to DOMV was low.