Factor analysis (FA) is a powerful method of testing the construct validity of coding systems of the medical interview. The study uses FA to test the underlying assumptions of the Verona Medical Interview Classification System (VR-MICS). The relationship between factor scores and patient characteristics was also examined. The VR-MICS coding categories consider the three domains of the biopsychosocial model and the main functions of the medical interview-data gathering, relationship building and patient education. FA was performed on the frequencies of the VR-MICS categories based on 238 medical interviews. Seven factors (62.5% of variance explained) distinguished different strategies patients and physicians use to exchange information, build a relationship and negotiate treatment within the domains of the biopsychosocial model. Three factors, Psychological, Social Inquiry and Management of Patient Agenda, were related to patient data: sociodemographic (female gender, age and employment), social (stressful events), clinical (GHQ-12 score), personality (chance external health locus of control) and clinical characteristics (psychiatric history, chronic illness, attributed presence of emotional distress).