In this study, aquatic environments adversely impact, which may occur in order to obtain information about the acute toxicity Fluazifop-p-butyl (herbicide) which is widespread used in agriculture in the Cukurova Region, has been researched using the larvae Oreochromis niloticus (L., 1754). In the present study, the test fish O. niloticus larvae (average weight 1.88 +/- 0.6 g, average length 5.04 +/- 0.5 cm) were obtained from the Cukurova University Fisheries Faculty Freshwater Fish Research and Application Station. In the experiment, five different concentrations along with the control group were used making a total of 12 aquariums. Each experiment was repeated two times. In this research, the static method of the acute bioassay methods was applied. The experiments were conducted under laboratory conditions at 25 +/- 2 oC. The results have been predicted with the dose-response data and were fitted with a log-logistic model by using R 3.0 statistical computation environment and DRC library. The 24-h acute LC50 value was determined. According to the conclusions, acute toxic effects investigated Fluazifop-p-butyl (herbicide), the 24-h LC50 acute toxic lethal concentration value for Oreochromis niloticus (L., 1754) larvae was calculated to be 1.94 +/- 0.02 mgl(-1). These results indicate that low levels of Fluazifop-p-butyl (herbicide) in the aquatic environment may have a significant effect on the O. niloticus populations.