The history of occupational health in Korea has covered the era of the Republic of Korea after the Liberation from Japanese colonialism. But the number of Korean workers exceeded about 2 millions at the times of liberation in 1945, so that it is expected that many occupational health problems inflicted Korean workers under the Japanese colonialism. The authors reviewed medical literatures, administrative documents, and other available data which were published under the colonial state, and collected things which had reference to the health status of Korean workers. The results were as follows; 1. Nutritional status of Korean workers was supposed to be inferior to of general population, some students, and poor inhabitants in a remote moutain villages. 2. It was supposed that the constitution of Korean workers was near lower limit of average build of contemporary Koreans. 3. The accidents rate in mines was significantly high but decreasing year after year, and the most importance cause of accidents was the fall of roof in the mine. The medical facilities and equipments for miners were supposed to be not sufficient in the mines and workshops. 4. Some occupational disease including silicosis, noise-induced hearing impairment, and decompression disease were known. But, overall incidence or prevalence of these diseases could not be identified. 5. On the whole, the fatalities of acute infectious diseases of Korean workers were higher than those of Japanese inhabitants in Korea and Korean inhabitants. The prevalence of pulmonary tuberculosis of Korean workers was increasing with every passing year. 6. The medical personnels and facilities were so deficient that most Korean workers were out of adequate medical use. We discussed only a part of the health status of Korean workers under the Japanese colonialism, so it would be necessary to have a better grasp of details of occupational health policy and health status in the era of afflicting.