To analyse the cardiac function of the Japanese domestic cat, several cardiac parameters were measured from arterial and intracardiac pressures in 34 adult cats. Under anesthesia with ketamine hydrochloride, catheters were inserted into the left and right ventricle and pulmonary artery. When stabilized in valve, leftventricular pressure (LVP), aortic pressure (PA), pulmonary arterial pressure (PPA), and right ventricular pressure (RAP) were measured to analyse the cardiac performance. All of them were analysed with a signal processor to get every cardiac parameter. The results obtained are as follows.