In the present study, we aim to evaluate the frequency of micronuclei and nuclear abnormalities in erythrocytes from zebrafish (Danio rerio), by the exposure of this species to different concentrations of triflumuron (Certero?), in acute (96 hours) and chronical (30 days) tests. In acute treatments the following concentrations of insecticide were used: 0,2 mL/L; 0,6 mL/L e 1,8 mL/L. In this tests there was complete fish mortality within 24 hours of exposure to the insecticide. In the chronicle treatment it was used the concentration of 0,2 mL/L. In this last test, there was no fish mortality before the end of the experiment, but through the statistical test it was verified that the triflumuron did not increase the frequencies of micronuclei and abnormalities in the blood cells of these animals.Neste trabalho buscou-se avaliar a frequ?ncia de micron?cleos e anormalidades nucleares em eritr?citos de zebrafish (Danio rerio), por meio da exposi??o desta esp?cie a diferentes concentra??es de triflumuron (Certero?), em testes agudos (96 horas) e cr?nico (30 dias). Nos testes agudos foram usadas as seguintes concentra??es do inseticida: 0,2 mL/L; 0,6 mL/L e 1,8 mL/L. Nesses testes, houve mortalidade total dos peixes em menos de 24 horas de exposi??o ao inseticida. No tratamento cr?nico foi utilizada a concentra??o de 0,2 mL/L. Neste ?ltimo n?o houve mortalidade de peixes antes do t?rmino do experimento, mas constatou-se por meio do teste estat?stico que o triflumuron n?o aumentou as frequ?ncias de micron?cleos e anormalidades nuclerares nas c?lulas sangu?neas destes animais
