The ICD-8 diagnosis applicable to borderline psychosis in children is psychosis limitaris infantilis (299.02). Results from a register-based study referring to all Danish children admitted between 1970 and 1992 and diagnosed borderline psychosis are presented here. A total of 415 children (332 boys and 83 girls) were admitted with a diagnosis of psychosis limitaris infantilis. At a follow-up examination in the Psychiatric Case Register 70 % of those diagnosed with psychosis limitaris infantilis were found to have been re-admitted at least once to a psychiatric hospital. Thirteen percent of the boys and 19% of the girls, admitted more than once, had a diagnosis of schizophrenia after 5 years. This share increased after a 15-year period of observation to 24 % in the group of boys, whereas the number of schizophrenic girls remained unchanged. One third of the boys and 17% of the girls were diagnosed with personality disorders, following a 15-year observation period.