Response of six wild sunflower genotypes including Helianthus petiolaris spp. petiolaris (E-142), Helianthus neglectus (E-017) and Helianthus annuus (E-060, E-173, E-174 and E-175) to drought stress imposed at the seedling growth stage was investigated in vivo . Plant height, number of leaves per plant, shoot fresh weight, root fresh weight, shoot dry weight and root dry weight were determined. Results indicated that the E-175 genotype belonging to Helianthus annuus was less affected by water stress conditions as compared to the other genotypes. Helianthus petiolaris spp . petiolaris (E-142) showed the highest sensitivity and had the lowest fresh and dry masses under drought conditions. In addition, this study showed that the number of leaves and root weight were the best selection criteria to determine drought resistance at the early vegetative stage. Water losses of the resistant genotypes in their roots and shoots in drought stress conditions were more than those of the sensitive genotypes.