Primary fibromyalgia syndrome (PFS) is a form of connective tissue rheumatism, characterized by diffuse chronic pain in periarticular tissue, for which no organic cause can be identified. The present study examined the personal and family history, clinical and psychodynamic features of 40 PFS patients, and compared them to a matched control group of patients suffering from rheumatoid arthritis. Depression, either in the past or at present, was seen significantly more often among PFS patients that among controls. Dependence and passivity, idealization of family relationships, obsessive-compulsive personality, maladaptive response to loss, and prepain ergomania were the psychodynamic features characteristic of PFS patients. It is suggested that PFS is a well-defined disorder, in which specific premorbid, familial, and psychodynamic characteristics result in a depressive disorder which takes the form of a physical symptom: pain.