Evaluation of the toxicity of Dicofol was carried out onAstyanax bimaculatus schubarti, a characteristic fish species living in tropical rivers and lakes. Experiments were under laboratory controlled conditions with atmospheric air flow and dilution water at 25°C in the static mode. Fish samples were collected and submitted to appropriate analytical procedure: Soxhlet extraction, clean-up by Florisil adsorbent and finally quantification by GC-ECD. The results showed good recoveries (> 89%) for the developed method both in water and fish samples. The lethal concentration, LC50, and the bioconcentration factor, BCF, were 18.13 mg L−1 and 241.70, respectively forAstyanax bimaculatus schubarti demonstrating the lipophilic nature of the studied compound.