This research paper presents the pathological effects of a sub-lethal concentration of heavy metals (cadmium, lead, nickel, and chromium) on common carp (Cyprinus carpio L.). Total protein and levels of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) in the liver tissue were measured. Compared with the control group a significant decrease of total protein (p < 0.001) was ascertained in the experimental group. The ALP on the other hand was significantly higher (p < 0.001). The values of ALT, AST, and LDH significantly decreased in the first day and then progressively increased afterwards (p < 0.001). The above results on the biochemical profile indicate marked hepatotoxic effects of heavy metals in common carp.