This research was carried out between 2007 and 2008 to determine drought tolerance of domestic and wild watermelon genotypes in Sanliurfa (Turkey) condition. A total of 32 wild and domestic watermelon genotypes were used in this experiment. Morphological and physiological treatments such as leaf relative-water content, leaf temperature, chlorophyll contents, leaf water potential, leaf color, leaf area, number of stomata, width of stomata, length of stomata, plant height, number of nods on the plant, plant dry matter ratio, main stem diameter, turgority and final drought resistance tests were examined. Drip irrigation treatments included complete irrigation cut off, dry (I-0), full irrigation based on replenishment of soil water depleted from 0-90 cm profile (I-1) and 50 % full irrigation (I-2). At the end of the experiment, fifteen genotypes (Kar-24, Kar-25, Kar-27, Kar-59, Kar-86, Kar-114, Kar-143, Kar-147, Kar-163, Kar-185, Kar-197, Kar-203, Kar-215, Kar-218 and Kar-224) were found as tolerant and seventeen genotypes (Kar-26, Kar-35, Kar-37, Kar-39, Kar-98, Kar-99, Kar-117, Kar-140, Kar-154, Kar-177, Kar-184, Kar-212, Kar-234, Kar-243, Kar-330, Kar-332 and Kar-325) were found as intolerant.