In an acute toxicity trail, LC50 and LC100value (96 hr) of endosulfan (END)+chlorpyrifos (CPF) mixture for Catla catla was computed. The genotoxicity of END+CPF mixture in RBCs of fish was also evaluated by comet assay. To check the genotoxicity of END+CPF mixture, blood of fish was sampled after 24-hr of intervals. Some fishes were also kept in
clean water known as negative control (NC) and for positive control (PC) cyclophosphamide was injected into fish. The tolerance limits of C. catla against END+CPF was computed as 1.35±0.01μgL-1(LC50) and 2.25±0.02μgL-1(LC100). Genotoxic results showed that END+CPF
mixture caused significant damage to nuclei (22.58±5.37%) and GDI (0.73±0.15%) in RBCs of fish as compare to control. Aduration-specific damage to DNA was observed in RBCs of C. catla.