BACKGROUND Blunt chest trauma can cause severe acute pulmonary dysfunction due to hemo/pneumothorax, rib fractures and lung contusion. OBJECTIVE To study the long-term effects on lung function tests after patients' recovery from severe chest trauma. METHODS We investigated the outcome and lung function tests in 13 patients with severe blunt chest trauma and lung contusion. RESULTS The study group comprised 9 men and 4 women with an average age of 44.6 +/- 13 years (median 45 years). Ten had been injured in motor vehicle accidents and 3 had fallen from a height. In addition to lung contusion most of them had fractures of more than three ribs and hemo/pneumothorax. Ten patients were treated with chest drains. Mean intensive care unit stay was 11 days (range 0-90) and mechanical ventilation 19 (0-60) days. Ten patients had other concomitant injuries. Mean forced expiratory volume in the first second was 81.2 +/- 15.3%, mean forced vital capacity was 85 +/- 13%, residual volume was 143 +/- 33.4%, total lung capacity was 101 +/- 14% and carbon monoxide diffusion capacity 87 +/- 24. Post-exercise oxygen saturation was normal in all patients (97 +/- 1.5%), and mean oxygen consumption max/kg was 18 +/- 4.3 ml/kg/min (60.2 +/- 15%). FEV1 was significantly lower among smokers (71.1 +/- 12.2 vs. 89.2 +/- 13.6%, P = 0.017). There was a non-significant tendency towards lower FEV1 among patients who underwent mechanical ventilation. CONCLUSIONS Late after severe trauma involving lung contusion, substantial recovery was demonstrated with improved pulmonary function tests. These results encourage maximal intensive care in these patients. Further larger studies are required to investigate different factors affecting prognosis.