In this study, 200 fish samples of Oreochromis niloticus and Clarias gariepinus(100 of each) were collected from different fish markets at Qalyoubia province. In addition, 100 skin swabs were collected from fish sellers (60) and house wives (40) from the same localities. The objective of this study is to detect the occurrence of some bacterial zoonotic microorganisms from market fish such as Staph. aureus, Salmonella spp., E. coli , and Streptococci and to detect the effect of heat treatment as frying and grilling on survival of inoculated (10) 4 Staph.aureus ,(10) 5 Salmonella typhimurium and (10) 6 E.coliO157H7 in both fish spp. In this study, it was evident that C. gariepinus samples had a significantly higher bacterial isolates (9.8%) than O. niloticus samples (6%). Among the isolated bacteria Streptococci was detectable at higher percentage (13.5%) followed by Salmonella spp (11.5%), then Staph. aureus (4.5%) and the lowest isolates were E. coli(2%).The higher percentage of bacterial isolates was recovered from surface samples than those isolated from muscle samples of both of the examined fish spp. Hand swabs of fish handlers revealed that Staph. aureus ,Salmonellae , E. coliand Streptococci were isolated at percentages of 35% , 35% , 20 % and 35% respectively from fish sellers compared to 37.5% , 25% , 37.5% and 50% respectively from house wives .Also these results showed that frying of fish lead to total destroying of inoculated pathogens in both fish spp. at different weights . While grilling not efficient as frying as it kill all the inoculated pathogens in O. niloticusbut not in large sized C. gariepinus. The public health importance of isolated microorganisms and suggested hygienic measures were discussed.