Chromium is highly toxic to both aquatic and soil environment. Aim of the present study was to determine acute effect of chromium trivalent (Cr- III) and hexavalent (Cr-VI) toxicity on climbing perch, Anabas testudienus (Bloch). The work was done using Finney’s Probit analysis method. The 96hr-LC of 50 Cr- III and Cr-VI was determined to be 305.0 and 39.0 mg/l by experimental fishes were exposed in different concentrations. The LC dose was more in Cr(III) in comparison to Cr(VI) as the difference was highly 50 significant. The work showed that acute chromium toxicity is severely affects the fundamental organs which are harmful to fishes in aquatic ecosystem. There is need to control the usage of chromium especially Cr-VI because of its observed toxicity level as Cr(VI) is more dangerous to aquatic organisms that Cr(III).