One of the most important environmental problems in the world is micro-pollutants. The aim of this study was to investigate the antioxidant responses of Gammarus pulex to Bisphenol A (BPA), an endocrine-disrupting agent. For this purpose, sublethal concentrations of BPA were applied to G. pulex and biochemical responses were studied. Enzymatic antioxidants superoxide dismutase (SOD) and catalase (CAT) activities and nonenzymatic antioxidants glutathione (GSH) and thiobarbituric acid reagents (TBARS) levels in G. pulex were determined in four different groups during 24 and 96h. Biochemical biomarkers were measured using commercial kits in a microplate reader. When we compared with control, SOD enzyme activity increased in all groups during both administration periods and CAT enzyme activity decreased in all groups. GSH and TBARS levels were increased after 24 and 96h of application periods in all groups when compared with control. For changes in SOD and CAT activities and GSH, TBARS levels have been determined to be useful as biomarkers against BPA in G. pulex tissues. It has also been proven that G. pulex is an effective bioindicator that shows BPA pollution in water. The different results of biochemical biomarkers can be evaluated as a marker of possible metabolic processes, and the biochemical response of G. pulex can reveal to some extent the environmental consequences of BPA pollution resulting from industrial waters.