Carnitine transporter defect is an autosomal recessive disorder caused by mutations in the SLC22A5 gene that encodes the high-affinity carnitine transporter OCTN2. Affected patients can present with predominant metabolic or cardiac manifestations. Early recognition of this disorder in a context of life-threatening cardiac failure and treatment with carnitine can be lifesaving in this inborn error of fatty acid oxidation. Here we describe a boy with a severe cardiomyopathy and severe anemia who improved with carnitine therapy. Physiopathology of anemia, a probably less recognized symptom of carnitine deficiency, is also discussed.