Smallpox contributed to the death of 300,000 people in Sweden between 1750 and 1800. It was one of the most feared diseases of the time. Most victims were children under the age of 10 years. It is estimated that one out of every ten children died from smallpox. The mortality rate was between 10% and 20% but those who survived faced severe complications. Most common were the disfiguring pockmarks among those previously infected. It turned out that women who had contracted smallpox married much later in life than the healthy. Also, both female and male fertility was lowered by smallpox infection. By the mid 1750s inoculation was introduced in Sweden. This was a preventive method where a mild infection was given by putting smallpox matter into an incision in the skin. Success was restricted to the wealthy, even if the doctors tried to reach the common people. The main reasons were lack of confidence for doctors, medical and epidemiological risks, costs and an ineffective organization. In 1801 Eberhard Zacharias Munch of Rosenschöld performed the first vaccination with cowpox matter in Sweden. In a few years an extensive practise was stabilized, which made the Swedish population one of the best vaccinated in the world. Moreover, a unique registration was compiled which, together with the parish records, makes the country one of the best documented. The main reasons behind the success was previous experiences of inoculation, international influences, abolition of the physicians monopoly, an effective organization, better opportunities for financing and rewards, and the compulsory law of 1816.