Abstract: The effects of CIPC treatment on starch phosphorylase (SP) and peroxidase (POD) enzyme activities of of Favorita were studied to clarify the mechanism of a sprout inhibitor CIPC action in stored potatoes, which were kept at room temperature and sampled from different parts of the tuber.The results showed that the enzyme activities of SP and POD in treated apical eye periderm discs were significantly lower compared with the control, and both enzyme activities were enhanced in treated lateral eyes due to the loss of apical dominance of Favorita and it showed no significant differences in other tissue of the tuber.Thus, the eyes of the tuber were more sensitive to CIPC than non-eye part.The main function of CIPC was on the eye parts of the potato.This might be regulated by affecting the endogenous metabolism.