Heavy metal (Mercury, lead, and cadmium) residues was appraised in various body weights of Tilapia fish gathered randomly from various regions at Cairo and Giza markets utilizing Atomic Absorption Spectrophotometer (AAS). The average estimations of mercury, lead, and cadmium residues in tilapia at weight up to 200 gm was 0.07±0.01, 0.1±0.02 and 0.0005±0.0001 ppm, respectively. While, the average values of mercury, lead, and cadmium residues in tilapia at weight 200-400 gm was 0.3±0.05, 0.2±0.02 and 0.03±0.01 ppm, respectively. Whereas, the mean values of mercury, lead, and cadmium deposits in tilapia at weight 400-600 gm was 0.6±0.06, 0.34±0.03 and 0.05±0.01 ppm, respectively. Heavy metal residues are positively correlated with fish size. Lead was the most elevated metal in tilapia up to 200gm. While Mercury was the highest metal in tilapia 200-600 gm. The outcomes were assessed by Egyptian Organization for Standardization EOS (NO. 7136/2010) and the public health hazards of heavy metal residues was debated.