Aim/Background: The study investigates the toxic impact of inorganic arsenic compound (sodium arsenate) on the freshwater crab Barytelphusa cunicularis. Sodium arsenate is a widely used chemical in various applications including insecticides, rodenticides, herbicides, antibacterial agents, and dye manufacturing, which can contaminate aquatic and terrestrial environments. Materials and Methods: The research conducted lethal concentration (LC50) tests using sodium arsenate on Barytelphusa cunicularis, analyzing the toxic effects at different exposure durations (24, 48, 72, and 96 hr). Statistical analysis was performed using SPSS with a 95% confidence level to determine the lethal and safe concentrations. Results: The LC50 values were found to be: 24 hr: 675.60 (645.96-38825) ppm, 48 hr: 657.32 (633.35-4062.70) ppm, 72 hr: 621.85 (605.32-645.02) ppm, 96 hr: 605.41 (589.92-615.39) ppm. The safe concentration for sodium arsenate was determined to be 186.68 ppm. Conclusion: The differentiation between mean LC50 values and safe concentration provides insights for developing conservative strategies to protect economically important crustacean species like Barytelphusa cunicularis from arsenic toxicity.