Western medicine began to be introduced to Japan since late 16th century. Japanese encounter with Western medicine centered on Dejima in Nagasaki in the seventeenth and eighteenth century and the initial process of introduction was gradual and slow. In the mid-nineteenth century, facing threats from Western countries, Tokugawa bakufu asked Dutch naval surgeon, J. L. C. Pompe van Meerdervoort to teach western medicine at the Kaigun Denshujo naval academy in Nagasaki. The government also supported the western medical school in Edo. This paper deals with how modern western medical doctors were developed in Japan from late Edo to early Meiji. The publication of the New Text on Anatomy in 1774 translated by Sugita Genpaku and his colleagues stimulated Japanese doctors and scholars to study western medicine, called Rangaku. During the Edo period, western medicine spread into major cities and countryside in Japan through Rangaku doctors. In 1838, for example, Dr. Ogata Koan established the Rangaku school named Tekijuku and educated many people with western medicine. When smallpox vaccination was introduced in Japan in 1849, Rangaku doctors played an important role in practiving the vaccination in cities and in countryside. After the Edo bakufu and the feudal lords of han(han) actively pursued to introduce western medicine to their hans by sending their Samurai to Edo or Nagasaki or abroad and by establishing medical schools and hospitals until their abolition in 1871. In late Edo and early Meiii military doctors were the main focus of training to meet the urgent need of military doctors in the battle fields of civil wars. The new Meiji government initiated a series of top-down reformations concerning army recruitment, national school system, public health and medical system. In 1874, the government introduced a law on medicine to adopt western medicine only and to launch a national licence system for medical doctors. Issuing supplementary regulations in the following years, the Meiji government settled down a dual-track medical licensing system: one for the graduates from medical schools with certain quality and the other for the graduate from less qualified schools who should take the licensing examination.