Deformed fish (Oryzias latipes), induced by diazinon, fenobucarb, trifluralin and cadmium, were observed with morphological, skeletal and histopathological methods. Deformed rate showed 49.2% in diazinon, 50.0% in fenobucarb, 96.1% in trifluralin and 14.5% in cadmium. The external signs the deformed fish exposed to the test substances were haemorrahge and scoliosis in the abdominal and caudal region. The observation of the skeletal system revealed that deformity mainly occurred between the 6th and 10th vertebra and the 15th and 24th vertebra, and that fracture occurred in the middle of centrum. Histopathological findings of the deformed fish were asymmetry of the body, severe fracture and dislocation of the vertebrae and displacement and disoirentation of the myotomal musculature. In addition the levels of abnormalities were similar with one another among the deformed fish in all the groups.