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Striga hermonthica is endemic in the semi-arid and semi-humid areas of Sub-Sahara Africa. This plant parasite reduces crop yields of maize and sorghum, the major staple food source of the region. Presently, there are no Striga-resistant maize varieties commercially available in Western Kenya. Striga resistant or tolerant maize would form an important part of an integrated control approach. To determine the response of the maize varieties most widely grown by farmers around Lake Victoria to Striga, a field experiment was conducted at two locations and over two seasons. The results showed a high variability among commercial maize varieties with respect to the effects of Striga parasitism. Short-cycle varieties have the lowest Striga densities but produce acceptable yields only in low-stress environments. Long-cycle varieties are too susceptible to Striga and are not completely adapted to the agroecological conditions of the region. Some medium-cycle varieties show level of resistance and/or tolerance to Striga while others supported high numbers of Striga and had reduced yield. Nevertheless, sufficient genetic variability exists to recommend varieties suitable to enable farmers to obtain some yield advantage by selecting those with the most Striga tolerance for a range of farming situations found in Western Kenya. (C) 2003 Elsevier Ltd. All rights reserved.