-Imazapyr has been used in Brazilian eucalypt cultivation for the maintenance of clearings and coppicing control in areas undergoing stand reform. However, inquiries have been made as to the final fate of the molecule. Imazapyr root exudation in eucalypt plants was evaluated through a bioassay under greenhouse conditions, by applying different herbicide doses (0.000, 0.375, 0.750, 1.125, and 1.500 kg ha -1 a.i.) on Eucalyptus grandis seedlings derived from vegetative propagation, hydroponically cultivated in 2.500 ml vases. Fortyday-old seedlings of the same clone were used as bioindicators, transplanted to the vases two days after herbicide application. After a period of 13 days of coexistence, the sprayed plants were removed and discarded; ten days later, the visual symptoms of toxicity were evaluated and the total dry biomass (aerial part and roots) of the bioindicators were determined. The lowest herbicide dose (0.375 kg ha -1 a.i.) affected the total biomass and growth, being most evident in the aerial part, with larger I 50 for root dry biomass. The E. grandis seedlings exuded imazapyr, and/or its metabolites, in concentrations capable of affecting the growth of plants of the same species.Keywords: Eucalyptus grandis, root exudates and herbicide. (0,000; 0,375; 0,750; 1,125; R. Árvore, Viçosa-MG, v.29, n.6, p EXSUDAÇÃO RADICULAR DE IMAZAPYR POR MUDAS DE EUCALIPTO CULTIVADAS EM SOLUÇÃO NUTRITIVA RESUMO -Na eucaliptocultura brasileira, vem-se utilizando o imazapyr para manutenção de aceiros e erradicação de cepas e brotações em áreas de reforma dos povoamentos. Entretanto, têm sido levantadas indagações quanto ao destino final da molécula. A exsudação radicular de imazapyr em plantas de eucalipto foi avaliada por meio de bioensaios em casa de vegetação, aplicando-se diferentes doses do herbicida