There are three identifiable phases in comparing vaccination policy in England, Prussia and Imperial Germany. (1) Prior to the 1870's the tradition of medical police in Prussia resulted in the vaccination of the population being treated as a State responsibility earlier than in England and provided an appropriate administrative framework. The administrative pressure that could be exerted persuaded the Prussian authorities that legislation to make vaccination compulsory was unnecessary. In contrast, England and Wales lacked both the tradition and administrative structures of a medical police. Legislation (1840, 1853) for free and universal infant vaccination was followed by radical ideological and administrative innovation. (2) From 1875 to 1889 both countries provided free and compulsory vaccination for all. In England this was limited to infants; in Germany including Prussia, it included the re-vaccination of children. (3) After 1889 England and Germany began to diverge more sharply. In England vaccination rates fell and after 1898 conscientious objectors were excused from having to have their children vaccinated. Germany retained compulsory vaccination and rates in the two countries increasingly diverged. England came to rely on the local public health administration for the surveillance and containment of smallpox, including selective vaccination of contacts. Despite these differences smallpox mortality dropped sharply in both countries, although in Germany somewhat earlier. The English reliance on surveillance and containment prefigures that of the WHO in the eradication of smallpox in the Third World. It suggests that the emphasis on the importance of high levels of mass vaccination in the German literature should perhaps be revised.