In 2000 and 2001 field trials were carried out to evaluate the efficacy of herbicide mesotrione in maize. The experiments were established in Zemun Polje and Smederevska Palanka, according to EPPO/OEPP standard methods. Trade formulation Callisto (a.i. mesotrione 480 g/L) used as a experimental sample in two doses 0.15 L/ha and 0.25 L/ha for pre-em, and 0.15 L/ha adjuvant; 0.25 L/ha + adjuvant and 0.25 L/ha alone for foliar application. The most sensitive weed species were: Adonis aestivalis, Amaranthus retroflexus, Cirsium arvense, Chenopodium album, Chenopodium hibridum Lepidium draba, Brassica nigra, Datura stramonium, Kickia spuria, Polygonum lapathifolium, Sinapis arvensis, Solanum nigrum, Stachys annua i Xanthium strumarium.