The major objective of this study was to investigate heavy metal content of black pomfret (Parastromateus niger ). The concentrations of Zn, Cu, As and Cd were determined in external (gill and shell) and internal organs (muscle and liver) of black pomfret in northwest of Persian Gulf in summer 2013. A total of 60 specimens were collected from fishing bottom trawlers. Concentrations of these heavy metals were measured by using atomic absorption spectrometer. Results showed that heavy metals concentrations varied significantly, depending on the types of the tissue in fish. Bioaccumulation of heavy metals Zn and Cu were in the sequence liver> shell> gill> muscle but for Cd and As were in the sequence of gill> shell> liver> muscle. In total organs and among heavy metals the accumulation of Zn and As were the highest and the lowest (P< 0.05). The results indicated that the gill of fishes were highly contaminated by heavy metals and exceeded of WHO and NHMRC guidelines for As and Cd, respectively.