Heavy metals are considered as the most dangerous water contaminants because of their possibility of bioaccumulation and toxic effects. This study tried to investigate the bio-availability of heavy metals in terms of Ni, Zn, Cu, Fe, Hg, Cd, and Pb in the sediment during dry seasons in Aras River basin located in Ardabil Province, north-west of Iran. Also the metal concentration in the skin and flesh carp was measured during all four seasons in 2010 in Aras River. Sediments were collected from five stations during summer but fish sampling was carried out seasonally in five fixed stations. The results of this study indicated that there was a meaningful and positive correlation between the existence of high levels of bioavailable metals and their concentration in fish body. Among the measured metals, Fe is highly bioavailable and the highest level of Fe in the sediment was in the ST4 (93.4mg/l). This could be due to high accumulation of this element in fish body. Also, maximum concentration of Fe in fish body was in summer (1.87mg/l) as well.