This thesis is a study on the change and the process of the development of the hygiene administration during the period of modernization of our nation which promoted by the open door policy of our country chiefly under the pressure of the foreign countries. During that period Korea had reorganized the old political system radically and introduced the western medical system. Through the close study of literature concerning the system of the hygiene administration, the laws of health and hygiene, the environmental sanitation organizations and their practical activities the author obtained the conclusions as following 1. The government passed around 40 laws of health and hygiene from the time when the bureau of hygiene was founded in 1894 to the annex of Korea to Japan. Most of the laws were believed to be established by the enforecement of Japanese government. When the epidemics were prevailing, a decree for the prevention of the epidemics was proclaimed by the Japanese president of the headquarters of national police. It is shown well that the sovereignty of Korea had been deprived. 2. After the armex of Korea to Japan, the hygiene police and the general police belonging to the bureau of national police shared the tasks of health and hygiene. This was a temporary system which had existed just during the colonial period. As for the water-supply which is the most important facility among the various environmental hygiene facilities, the rate of supply was remarkably high in Japanese rather than in Korean. 3. During the period of American military administration, it is notable that the division of hygiene in the bureau of national police was replaced by the bureau of hygiene. This period is regarded as the turning point when hygiene administration was operated by means of education along with the introuction of American system of public health. 4. Ever since the foundation of the republic government, the laws of health and hygiene which had been established during the colonial period have been put into operation without rriuch change except several regulations concerning food.