Abu Za'baal Lakes are man-made lakes, formed by the fracture apd extract of rocks. The lakes, as other inland closed basins. receive their water from the ground and seepage waters. They consist of three lakes and another filling-phase lake. In the present study, the concentrations of some heavy metals {Fe. Zn. Mn. Pb. Cu and Cd) in water and organs (muscles, gills, liver and kidney) of O. niloticus. T, zillii and C. iazera collected from Abu Za'baai Lakes were measured during winter. 2004. The effects of the tested metals on the total protein and total lipid contents in the muscle and liver and on the histological structures of the gills. liver and kidneys of fish were studied.The present results showed that the levels of Fe. Zn. Mn. Pb. Cu and Cd in the water of Abu Za'baal lakes ranged between 3.22-6.0L 0.21-1.50. 0.67-1.64. 0.62-1.67. 0.13-0.20 and 0.03-0.06 mc/L respectively. The highest \ allies of metals were reported in the third lake, while their lowest values were in the first one.It was found that the metals were accumulated in different organs of the studied fish b> various levels. The concentration of the tested metals in different organs of (I niloticus and T zillii followed a sequence of: Fe. /n. Mn. Pb and Cd in muscles < gills < liver < kidnevs. however. Cu in muscles • uills < kidnevs < liver for (). nilolicus and in gills ■■ muscles ■ kidneys < liver for T. zillii. On the other hand, in C lazcra. Fe and Cu were in muscles < gills < kidneys < liver. Zn. Pb and Cd in muscles •' gills < liver --' kidneys and Mn in muscles < li\er - kidne\> gills. In general, the concentrations ol the tested r^.iab: -o. drfforcnt organs of the studied fish were in the following oider. F~ > Zn > Pb > Mn > Cu > Cd. Zn,- Cu and Cd concentrations in the fish muscles (edible parts) (except Cd in the muscles of T. zillii) were within the maximum permissible limit. The concentrations of Fe and Pb in the muscles exceeded the permissible limit.The total protein content in the muscle and liver of O. niloticus. T, zillii and C. lazera showed non significant decrease. Otherwise. the muscle lipid consent snowed highly significant increases in O. niloticus and T. zillii and non significant decrease in C. lazera. In contrast, the liver lipid content rhowed non significant increase in O. niloticus and T. zillii and a highly significant increase in C lazera.Several histopathological alterations were observed in the gills, liver and kidneys of the studied fish collected from Abu Za'baal Lakes.