Background: In a context of increasing concern for complex care needs in medical patients, this study is intended to document the utility in pneumology patients of INTERMED, a reliable and valid instrument to assess case complexity at the time of hospital admission. Methods: Three hundred and fifteen consecutive patients were assessed at hospital admission with INTERMED by a trained nurse. At discharge, independent research workers, blind to the previous results, reviewed the medical database and a subsample (n = 144) was assessed for psychopathological outcome. Severity of the pulmonary disease was assessed with the Cumulative Illness Rating Scale (CIRS), and psychopathology with the Hospital Anxiety and Depression Scale, Mini-Mental Status Examination (MMSE) (cognitive disturbances), and CAGE Scale (alcohol abuse). Operational definitions were used for measures of care complexity. Results: Most patients were in geriatric age, and 78 patients (24.7%) were classified as "complex" by means of INTERMED (IM+). In support of the working hypotheses, IM+ patients scored significantly higher in measures of care complexity (Cumulative Illness Rating Scale, "number of consultations during admission" and "diagnostic count") and on both anxiety and depression. INTERMED was also associated with length of hospital stay (LOS) and with both anxiety and depression after controlling for significant predictors and socio-demographic data. Conclusions: This is the first report about the ability of INTERMED to predict complexity of care in pneumology patients, and the first to predict a negative psychopathological outcome in any type of medical patients.