BACKGROUND: We investigated whether children and adolescents who survive cancer are at increased risk for psychiatric hospitalization. METHODS: In a nationwide, population-based, retrospective cohort study, 3710 persons who survived at least three years after a diagnosis of cancer in childhood or adolescence in the period from 1943 to 1990, and who were alive on January 1, 1970, or were born after that date, were identified in the Danish Cancer Registry. This population was followed up for psychiatric hospitalization from January 1, 1970, through 1993 by linkage with the Danish national Psychiatric Central Register. The number ofexpected cases was based on the national rates of hospitalization for psychiatric disease. RESULTS: Among the 3710 survivors of cancer in childhood or adolescence, there was a total of 88 psychiatric hospitalizations. The risk of hospitalization for any psychiatric disease was higher among the survivors than in the general population, but the excess risk was restricted to survivors of brain tumor (the standardized hospitalization ratio [SHR], corresponding to the ratio of observed to expected cases of hospitalization for psychiatric disease, was 1.8; 95 percent confidence interval, 1.5 to 2.2). An increased risk of psychoses of somatic, cerebral causes (SHR, 7.7; 95 percent confidence interval, 4.1 to 13.2), psychiatric disorders in somatic disease (SHR, 5.1; 95 percent confidence interval, 2.5 to 9.1), and schizophrenia and related disorders (SHR, 2.4; 95 percent confidence interval, 1.2 to 4.4) was observed among survivors of brain tumor. There was no evidence of a significantly increased risk of major depression. CONCLUSIONS: The risk of hospitalization for a psychiatric disorder is not increased among survivors of cancer in childhood or adolescence, except among survivors of brain tumor.