Abstract: The general purpose of this study is investigating the degree of heavy metal accumulation in scales, livers and gonads of the Cyprinus carpio and determining fish scale as the most suitable bioindicator for lead and zinc sedimentation in the environment of the sampling stations. Also, amounts of lead and zinc in the livers, scales and gonads tissues of the Cyprinus carpio are measured and a comparison is made between the amounts measured in the sediments and those measured in the livers, gonads and scales of the fish. Five sampling stations at different districts in the following cities were chosen: Astara, Hashtpar, Bandar Anzali, Ramsar and Chalous. Samples were prepared and classified according to fish organs as sedimental samples, liver samples, scale samples and gonad samples and then lead and zinc levels were measured in them. Results of this study show that fish scale is a better index of zinc content than liver and gonad in addition; fish scale is a better index of lead content than gonad. As no strong correlation was found between lead pollution level in the environment and that in fish scales, it was concluded that fish scale is a weaker index for lead than for zinc. The results obtained of the bioaccumulation of lead in the related tissues was found to be in the following order: Liver average < Female gonad average < Sediments average < Male gonad average < Scales average. The bioaccumulation of zinc in the studied tissues was found to be in the following order: Male gonad average < Sediments average < Female gonad average < scales average < Liver average.