Dilated cardiomyopathy (DCM) is characterized by ventricular systolic dysfunction, cardiac chamber dilation, elevated filling pressures, and myocardial hypertrophy with increased heart weight1,2. Historically, cats had a high incidence of dilated cardiomyopathy and often presented clinically with end-stage heart failure3. The initial report by Pion et al.4 of an association between low plasma taurine concentrations and DCM was based largely on clinical cases. Additional evidence of this association has recently been reported by Sisson et al.5 from a multicenter study of clinical cases of DCM in cats. In the present study a more direct cause-and-effect relationship between taurine deficiency and myocardial dysfunction was sought through use of a purified taurine-free diet to induce taurine deficiency in vivo. Isolated, perfused left ventricular preparations were subsequently used to evaluate cardiac function in vitro. Results from these studies have been previously reported elsewhere6.