Large-scale field trials were performed in an endemic focus of cutaneous leishmaniasis in both urban and rural settlements of Swanliurfa City, SE Anatolia, Turkey, to evaluate the efficacy of insecticide impregnated bednets. An intervention field trial promoting the use of K-OTAB (deltamethrin-tablet formulation) impregnated bednets by the local inhabitants of five quarters for cutaneous leishmaniasis was performed between July 2000 and July 2001. The aim was to examine the monthly and annual efficacy of such bednets in controlling cutaneous leishmaniasis and to compare effect of impregnated bednets (113) with non-impregnated bednets (NIB). Results showed significant (P<0.05) reduction in cutaneous leishmaniasis incidence in the intervention areas from 1.87% to 0.035% in Yenice and from 2.3% to 1.32% inSuruc B. In contrast, cutaneous leishmaniasis incidence increased in the untreated control areas from 1.03% to 1.38% in Suruc A. The annual incidence of the second control area for cutaneous leishmaniasis experiments showed almost no change at all (1.1% in July 2000; 1.02% in July 2001). Similar to results of control areas, cutaneous leishmaniasis incidence rates showed an increase despite the bednets in the Suruc C (1.22% to 1.47%) where NIBs were distributed.