SUMMARYObjective— To discuss the contribution of epidemiology and epidemiological methods to psychosomatic medicine.Method— Critical review of the literature, including both philosophical concepts and empirical data.Results— The adjective «psychosomatic» has been used in two different ways: in the so called «psychosomatic» or holistic approach to medicine; and in a narrower approach, referring to particular disorders in which psychological factors were considered to have a fundamental aetiological role. While the ideal of the holistic, «humanistic» or «anthropological» approach should probably be never abandoned, the practical limitations of encompassing models, including Engel's bio-psycho-social model are also obvious: they may be heuristically sterile. On the other side, in relation to the narrow psychosomatic approach, psychogenetic views in the so called «psychosomatic illnesses» have been strongly criticized on empirical grounds. The potential of epidemiological methods to study these illnesses, but also «somatopsychic» disorders is shown in a number of papers in the empirical literature. We have grouped such contributions, including our own experience, in the five categories suggested by M. Shepherd for epidemiological methods in general: 1) the completion of the spectrum of disease; 2) the establishment of outcome; 3) the actuarial assessment of morbid risk; 4) the evaluation of the efficacy of treatment; and 5) the conceptual construction of diagnosis and classification.Conclusions— The contribution of epidemiological data to areas of interest in psychosomatic medicine has been relevant in recent years. The potential of epidemiological methods in this area is very important both to increase knowledge and to improve the quality of clinical practice.