Abstract: A simple leaf tip assay was used for screening of putative transgenic plants expressing the hygromycin resistance gene (hph) or kanamycin resistance gene (nptll). Leaf tips were excised from in vitro or in vivo transgenic plants and cultured on MS medium without phytohormons containing the suitable concentrations of hygromycin and kanamycin. Leaf tips of plants transformed with the marker gene showed no significant effect of the appropriate drug for at least two weeks. While non-transgenic leaf tips had noticeable symptoms of bleaching, necrosis or browning after 3-4 days of selection. This method is simple, rapid and allows clear distinction between transformed and non-transformed plants both, in monocots and dicots.