Agrand total of eighty random samples of Tilapia nilotica and Clarias lazera ( 40 of each ) were collected after catching in Shebin El-kom , Menofia Govemorate. The samples were directly transferred to the laboratory for determination of their contents of mercury , lead and cadmium. The evaluation revealed that the mean values of mercury concentration ( mg/kg ) in the examined fresh water fish were 0.46 ± 0.03 mg/ kg for Tilapia nilotica and 0.52 ± 0.04 mg/ kg for Clarias lazera . Furthermore ,the mean values of lead concentration ( mg/kg ) in the examined samples of Tilapia nilotica and Clarias lazera were 0.08 ± 0.02 and 0.14 ± 0.02 mg/ kg , respectively . Also, the mean values of cadmium concentration in the examined samples of fresh water fish were 0.10 ± 0.01 mg / kg for Tilapia nilotica and 0.14 ± 0.02 mg/ kg for Clarias lazera . The public health importance of such heavy metal residues were discussed .