A total of 158 cases of parathion poisoning were clinically observed in Chonnam Univ. Hospital from Jan., 1968 to June, 1972 with the following results. 1. The males were 133 and the females, 25 with 93 patients in the age group of 21 to 40 years old and the majority of the patients were farmers. 2. 158 cases could be devided into 38 cases of inhalation group and 120 cases of ingestion group. The group I entirely occurred byingestion of the parathion for the suicide purpose. 3. During the period from 1968 to 1972, more frequent incidence of parathion poisoning showed up in 1971 and 1972,. 4. Most patients came to our Hospital within one or two days after admissioni. 5. Clinical signs and symptoms showing high incidence were bronchorrhea, dyspnea, vomiting, abdominal cramps, sialorrhea, tachycardia, miosis, fasciculation, hypertension, drowsiness and confusion, leukocytosis, elevation of SGOT, whereas mydriasis, and proteinuria were low in incidence. 6. Roentgenographs of the chest were taken to 39 cases out of a total of 158 cases and revealed 21 cases of normal chest, 11 cases of bilateral pulmonary congestion, 7 cases of pulmonary edema or pneumonic consolidation.