Orobanche spp. (broomrapes) are holoparasitic angio-C, sperms that subsist on the roots of dicotyledonous plants. Broomrapes are the most destructive weeds since they extract water and photosynthate directly from crop plants, causing crop yield and quality to reduce significantly. The occurrence of total superoxide dismutase and total peroxidase activities during broomrape-sunflower interaction were studied on three different cultivars (cv. Pioneer 4223, cv. Sanay and cv. Isera) of Helianthus annuus. Total superoxide dismutase activities increased on day 7 post-inoculation in cv. Pioneer 4223 and cv. Isera compared with control plants, whereas a decrease during all days in cv. Sanay was observed. In the variety of Orobanche-resistant cv. Pioneer 4223, the increases in the total superoxide dismutase activities were supported by the total peroxidase activities in the first 5 days, which indicate that the detoxification of the reactive oxygen species produced during the Orobanche penetration seems to be related to the Orobanche resistance in the sunflower. An increase has been determined in the total SOD activities from the first to the seventh day, but this increase was not found parallel to that in the total POX activities in cv. Isera.. This situation may indicate sensitivity for cv. Isera. Total peroxidase activities increased for the first 7 days in cv. Sanay compared with control plants. Total superoxide dismutase and total peroxidase activities were not a statistically significant change during all days in treatment plants compared with control plants in cv. Sanay. This change in SOD activities may indicate sensitivity of both cv. Isera and cv. Sanay to broomrape unless they are treated with herbicide.