The case of a girl who presented with gastrointestinal upsets with nausea, vomiting and occasional hypoglycaemic attacks during childhood is reported. At about 5 years of age generalised muscular weakness with severe amyotrophy, cardiomegaly with a cardiothoracic ratio of 0,63, left ventricular hypertrophy on electrocardiography and left ventricular dilatation with hypokinesis on echocardiography were observed. A few weeks later she developed severe cardiac failure. Muscle biopsy showed muscular dystrophy with lipid infiltration due to carnitine deficiency )serum carnitine 9 nmoles/ml, normal values: 46 +/- 6,9 nmoles/ml; muscle carnitine 0,27 nmoles/mg, normal values: 3,0 +/- 0,79 nmoles/mg fresh frozen weight). She improved rapidly with carnitine chlorhydrate and a diet low in lipids and high in medium chain triglycerides. Regression of muscular symptoms and cardiac failure was observed. After 13 months follow-up with no tonicardiac therapy she is much improved; the signs of heart failure have disappeared, the cardiothoracic ratio is now 0,55 and the electrocardiogramme and echocardiogramme are normal.