The freshness and hygienic quality of 50 fresh Tilapia sold in Port-Said fish market were evaluated. Quality grades based on the sensory evaluation of general appearance, odor, texture and condition of eyes and gills showed that 26% of the examined Tilapia were of grade (E), the excellent quality followed by 56% of grade (A) and 18% of grade (B). The quality levels based on the microbial load, showed that the accepted percentage of samples for human consumption according to; total viable count (TVC), total coliform bacteria (TC), S.aureus count, total Vibrio spp. count and Salmonella spp. were; 80%, 56%, 94%, 100%, and 100% respectively. Salmonella could not be detected in any of the examined samples, only 6(12%) of samples have S.aureus with mean count of 5.1x10¹±0.114cfu/g. Coagulase  positive S.aureus was further examined for their ability to produce enterotoxins and only four isolates were found to be enterotoxin  type B producers. The microbiological quality of fish was markedly improved by heat treatment (boiling for 10 minutes); The TVC, TC decreased to <100cfu/g, <10 cfu/g respectively and no pathogenic bacteria (S.aureus, Salmonella and Vibrio spp.) could be detected in the treated samples.