The real utility of high resolution computed tomography (HRCT) for early detection of lung involvement was investigated in eighteen patients affected with systemic sclerosis (SSc). The results obtained from HRCT have been compared with traditional (chest radiographs, pulmonary function tests (PFT)) and nontraditional (ventilation and perfusion scintiscan) modalities of lung investigation. A significant statistical correlation (p < 0.001) between HRCT scans and chest radiographs was observed. Moreover, HRCT was more sensitive in the detection of early pulmonary interstitial involvement and more accurate in the assessment of interstitial fibrosis in cases with severe lung involvement. A statistical correlation (P < 0.001) between HRCT and the modalities of investigation of alveolo-capillary membrane--as PFT and ventilation scintiscan--was also observed. These results indicate that in SSc HRCT may be a useful technique for assessing early pulmonary involvement and for complementing other methodologies of investigation of lung function.