Rickets caused by poor nutrition was widespread in Norway at the beginning of this century. Today it is a very rare disease among Norwegian children. During the last 20 years, however, it has become quite common among immigrant children who have come from developing countries to live in Norway. This is probably due to a combination of different factors such as material vitamin D deficiency, lack of vitamin D supplementation, long-lasting breast feeding, latitude (therefore little sunshine in winter) and lack of exposure to sunshine during the summer. The paper reviews the disease, with a special emphasis on clinical findings, diagnosis, treatment and prevention.