Survival from cancer in childhood and adolescence was studied in 8312 children aged 0-19 years notified to the Danish Cancer Registry during 1947-1987. During the first period (1943-1972), five-year survival rates from all malignant neoplasms increased from 23% (1943-1952) to 33% (1963-1972). The greatest improvement was seen during the period 1973-87 when five-year survival rates reached 64% (1983-1987). Between 1973-1977 and 1983-1987, five-year survival rates increased from 32% to 62% for leukaemia, from 40 to 70% for acute lymphoblastic leukaemia, from 35 to 54% for non-Hodgkin's lymphoma, from 50 to 66% for central nervous system neoplasms and from 25 to 49% for bone tumours. An improvement in five-year survival rates for Wilms' tumour was seen between 1960 (19%) and 1980 (81%). Up to 1972, the five-year survival rate from germ-cell neoplasms was approximately 40%; among patients diagnosed in 1973-1987, 76% survived for five years. Survival was similar for boys and girls during the early period, but was significantly higher for girls subsequently. A marked effect of age at diagnosis was seen in the early registration period where survival rates for the age group 0-9 years was substantially lower compared to the age group 10-19 years. This inequality persisted only for children less than two years of age in the later period.