SummaryThe evidence linking pain and depression is briefly reviewed. This evidence suggests that in the presence of more depressive symptoms painful conditions or stimuli are experienced as more severe. Recent ideas from the field of pain research have shown that pain has three components: sensory, affective and evaluative. Furthermore, pain transmission can be altered by the behavioral state of the person through the action of a pain-modulating system. A model is presented whereby factors controlling the patient's affect and cognition alter that patient's behavioral state, which in turn alters pain transmission through central nervous system modulatory networks.