Sweden has a very long pediatric tradition. In 1764 Nils Rosen von Rosenstein published his famous book "Diseases of Children and their Remedies". Fredrik Berg was appointed the world's first professor of pediatrics in 1845. Oscar Medin, who was a professor of pediatrics, initiated in 1900 the founding of "The Pediatric Society in Stockholm", which became associated with the scientific organization "Swedish Society of Medicine". Organizational and educational issues began in 1936 managed by a new organization called the "Swedish Pediatric Association". The initiators of this society were strong organizers who successfully approached all members of county councils and the Swedish parliament and requested that a pediatric hospital should be established in every county. Thus, during a time span of 20 years the number of pediatric clinics increased from 11 to 40. Another successful action led to the creation of posts as head pediatricians who were responsible for the child health service in each county. The scientifically and the organizationally oriented pediatric associations merged in 1970 to become the "Swedish Pediatric Society". A special feature for pediatrics in Sweden has been an early interest in social and psychiatric problems. Up to 1970 all head pediatricians and professors at some time had been working at child welfare clinics and many of them had also worked as physicians in schools, which meant that doctors in the primary care could count on good knowledge and understanding of their problems from centrally working colleagues. In 1930 a successfully performed pediatric international congress took place in Stockholm. Since then an intense international cooperation has taken place. In the decades after the war many Swedish students and researchers stayed for a year or more in foreign universities and at the same time students and doctors from abroad came to visit the Swedish universities. The pediatric associations invited groups of pediatricians from several countries to visit different hospitals and universities in Sweden. Later on groups of Swedish doctors were given the opportunity of making similar visits to their former guests.