The Kor River (Fars province) was divided into three parts and water and fish specimens were collected monthly and the concentrations of four heavy metals were determined using the Induction Coupled Plasma Method. As middle sampling zone was the main entrance and discharges of industries into the River, the concentrations of heavy metals in tissue of fish from this zone were significantly higher (p < 0.05) than those from the other two sampling zones, whereas no significant differences (p > 0.05) were detected between the two sexes and species. Maximum concentrations of lead, mercury and cadmium in fish tissues were higher than the permissible levels for human consumption. Significant changes in the concentrations of steroid hormones were also noticed between the middle and two other sampling zones. Also in middle sampling zone, pathological changes in blood cells, liver, and kidneys of fishes were significantly higher. So heavy metals exposure can effectively decrease estrogenic and androgenic secretion in fish. The results confirmed exposure of fishes to heavy metals not only disrupts reproductive hormones’ secretion, but also induces some pathological changes.