A survey of 472 chronically ill and disabled Norwegian adults with four different main diagnoses (asthma/allergy, hemophilia, osteogenesis imperfecta and rheumatic disease) was carried out during a period of 3 years. The purpose was to analyse the factors influencing their use of available Social Insurance and Welfare services. The participants were interviewed and their medical records studied. Compared to the total population their level of education was lower and fewer were active in the work force. Available social insurance benefits had been obtained by almost half of the patients with hemophilia and osteogenesis imperfecta, but very few with asthma/allergy and rheumatic disease. Patients with high family income and/or high educational level had received relatively more social insurance benefits than others. Men had obtained more benefits than women and young patients more than the older ones. The need for practical welfare services was high, particularly in families where a parent or daughter looked after the patient, where the patient had several additional diagnoses, and among the female patients. There was a higher unmet need for welfare services among patients suffering from asthma/allergy and rheumatic diseases than among those with hemophilia and osteogenesis imperfecta. There were marked regional differences in the granting of both social insurance and welfare services.