Abstract: A tissue section electrode sensitive to cytochrome C has been made by using a thin slice of porcine kidney coupled with an oxygen electrode. Over the concentration range of 0.01 to 0.227 mg/ml of cytochrome C, the dynamic response of electrode is linearly related to the logarithm of the concentration of cytochrome C and the correlation coefficient is -0.9949. Some experimental factors such as buffer composition, pH, temperature, tissue slice thickness and preservative agent were investigated in detail. The probe is usable for up to 1～2 weeks The average recovery of cytochrome C assay determined by the dynamic response method was 98.8%, with a standard deviation of 3.4%.