The accumulation of heavy metals such as lead (Pb), iron (Fe), zinc (Zn), cadmium (Cd), and chromium (Cr) was examined in crab (Scylla serrata) and shrimps (Penaeus semisulcatus, Penaeus indicus, and Penaeus monodon) collected from Pulicat lake that receives effluents from industries located in north Chennai, southeast coast of India. The results showed limited difference between crab and prawns as well as significant variations between the organs. Pb is the highly accumulated metal in both crab and shrimps, except P. monodon. The highest metal concentration was mostly found in the liver followed by other organs. The concentration of metals in edible parts (muscle) was within the permissible level and safe for consumption. However, the results of the study clearly indicate the biomagnification of metals in Pulicat lake.