The aim of the study was to investigate the pulmonary parenchymal abnormalities by high resolution computed tomography (HRCT) in patients with various forms of scleroderma. Three scans were performed sequentially in all cases: one at the level of aortic arch, one at the tracheal carina and one 1-2 cm above the diaphragm. Seventy cases with limited, 21 patients with diffuse cutaneous systemic sclerosis and 10 cases with circumscribed scleroderma were investigated. The 21 patients with diffuse scleroderma included three normal HRCT scan (14%), three with ground glass attenuation (14%), one with ground glass attenuation with fibrosis, three with fibrosis (14%), six with subpleural and five with diffuse honeycombing. The majority of cases with extensive honeycombing of the lungs had anti-Sc! 70 autoantibody which was the characteristic antibody of the diffuse scleroderma subset. The 70 cases with limited cutaneous systemic sclerosis were characterized by normal HRCT (43%), ground glass opacity with or without fibrosis (18.6%), whereas fibrosis was detected in 22.9%, subpleural or diffuse honeycombing in 15.7% of the patients. Six of the ten cases with circumscribed scleroderma also showed a fibrosis. Cases with diffuse scleroderma are characterized by the presence of advanced fibrosis, whereas the extent of fibrosis is far less pronounced in limited scleroderma. Mild fibrosis may also be present in circumscribed scleroderma forms.