Peroxidase (PO) activity was assessed in different sugarcane cultivars varying in red rot resistance. Moderately resistant (MR) cultivars showed higher accumulation of PO enzyme in stalk tissues when compared to moderately susceptible (MS) and highly susceptible (HS) cultivars. The rate of increase in enzyme activity was higher after pathogen inoculation in MR cultivars than in MS and HS cultivars. The MR cultivars showed higher enzyme kinetics peak values than other cultivars and the peaks were observed much earlier as compared to MS/HS cultivars. PO isozyme studies clearly indicated that after pathogen inoculation in internodal tissues, isozyme profile is altered. Certain PO isoforms disappeared after inoculation or intensity of certain other isoforms increased in sugarcane cultivars. Comparison of PO isozyme profile after pathogen inoculation at different intervals revealed more prominence of PO isozymes on the 4th and the 6th day after pathogen inoculation. Eight days after pathogen inoculation intensity of PO isozymes reduced. In HS and MS cultivars the intensity of PO isozymes reduced 10 days after pathogen inoculation whereas, in MR cultivars the intensity was maintained throughout the study period.