OBJECTIVE To describe the clinical and functional findings recently reported in the medical literature for patients diagnosed with emphysema involving the upper lobes and idiopathic pulmonary fibrosis (IPF) involving the lower lobes. METHODS Eleven patients with emphysema and IPF were identified retrospectively. All of the patients underwent high-resolution computed tomography of the lung and pulmonary function tests. RESULTS Of the 11 patients, 8 were male and 3 were female. The mean age was 70.7 +/- 7.2 years (range, 61-86 years). All of the patients were smokers (mean smoking history, 61.5 +/- 43.5 pack-years). The mean values of forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and FEV1/FVC were 72.1% +/- 12.7%, 68.2% +/- 11.9% and 74.4 +/- 10.8, respectively. Lung volumes were normal in 7 patients. A restrictive pattern was observed in 3 patients, and hyperinflation was present in one. The diffusing capacity was moderately-to-severely reduced in all of the patients (mean, 27.7% +/- 12.9% of predicted). Ten of the 11 patients performed the six-minute walk test. The mean distance covered was 358.4 +/- 143.1 m, and 9 of the 10 patients presented desaturation >or= 4%. Echocardiographic findings suggestive of pulmonary hypertension were present in 4 patients (mean systolic pulmonary artery pressure, 61.8 mmHg; range, 36-84 mmHg). CONCLUSIONS The concomitant presence of emphysema and IPF causes characteristic changes on pulmonary function tests. The most significant finding is a discrepancy between diffusing capacity and spirometry results.