Abstract: Due to different human activities in the vicinities of Aras dam, various pollutants such as heavy metals are entered into the reservoir and thus polluting the aquatic ecosystem. As a result, this heavy metal is accumulated in the tissues of Astacus leptodoctylus, which is considered as one the abundant species of crayfish that has got important food values and is of economic importance due to its export to other countries. In this research, the bioaccumulation of heavy metals in different tissues of this animal is taken into consideration. The concentration of Fe, Cu, Zn, Mn, Pb, Ni, Co and Cr among the tissues of female and male Astacus leptodactylus has been determined. The highest concentration of Cu and Fe was found in the gills and the highest level of Zn was found in hepatopancreas. Besides, the highest Mn concentration was recognized in exoskeleton. Furthermore, no significant difference was found between the male and female crayfish in the concentration of the heavy metals in their tissues, except for the concentration of some of the metals such as Fe in some of the tissues such as hepatopancreas.