The Illness Perception Questionnaire (IPQr) is a validated psycho-social tool. Chronic illness out-patients, 48 women and 42 men, 61.36 +/- 14.55 yrs, showed a social stigma related to illness condition, even common and scarcely invalidating, more evident with a lower degree of instruction, associated to limited cognitive representation and to inappropriate control. Duration of illness directly influences perception of "chronicity"; age, instead, positively influences compliance and trust of patients. The study of illness perception, aimed to foresee, interprets and modifies behavioural patterns in health and disease, according to implicit and/or hidden personal and/or social theories, it can improve quality of clinical medical approach.