Ninety random samples of fresh fish (Claris gariepinus, Oreochromis niloticus and Mugil cephalus, 15 of each) and shellfish (Oyster, Shrimp and Crab, 15 of each) were collected from different fish markets in Kalyobia governorate, Egypt, for determination of histamine and cadaverine levels in their tissues. The obtained results revealed that, the mean value concentrations of histamine in fish samples were 21.59 ±1.72;18.31 ±1.45 and11.64 ±1.19 for Claris gariepinus, Oreochromis niloticus and Mugil cephalus, respectively. Meanwhile, in shellfish samples and they were 41.75 ±3.26;33.08 ± 2.57 and 19.92 ± 2.02 for Oyster, shrimp and crab, respectively. In addition, mean value concentrations of cadaverine in fish samples were 17.86 ±1.40;16.57 ± 1.24 and 8.94 ± 0.76 for Claris gariepinus, Oreochromis niloticus and Mugil cephalus, respectively. The average concentrations of cadaverine in shellfish samples were of 29.16 ± 2.05;21.83 ± 1.61 and 13.09 ± 1.14 for Oyster, shrimp and crab, respectively. It could be inferred that regarding the products contamination, the highest histamine contamination was in oyster followed by shrimp followed by Claris gariepinus then crab then Oreochromis niloticus finally Mugil cephalus. Whereas the highest cadaverine contamination was in oyster followed by shrimp followed by Claris gariepinus then Oreochromis niloticus then crab finally Mugil cephalus.