ABSTRACT: Carnitine and acylcarnitines were measured in plasma and tissues of control turkeys, turkeys with an inbred spontaneous cardiomyopathy, and turkeys with furazolidone- induced cardiomyopathy. Heart failure was evident in both types of cardiomyopathy from decreased systemic blood pressure and cardiac dilatation compared to controls. Plasma free carnitine, short-chain acylcarnitine, and long-chain acylcarnitine were significantly elevated by 76 to 614% (p < 0.01) in the two cardiomyopathy models compared to control. The highest carnitine levels were found in the most hypotensive turkeys. Liver free carnitine and short-chain acylcarnitine levels were also elevated by 45 to 537% (p < 0.05) in both types of cardiomyopathy. Free carnitine was elevated by 126% in left ventricle and by 54% in skeletal muscle of the furazolidone-treated turkeys (p < 0.05). We speculate that hepatic synthesis of carnitine may be increased in response to hypotension and progressive cardiac dysfunction in cardiomyopathic turkeys. Such an increase may be useful to promote β-oxidation of fatty acids as a cardiac energy source.