The objective of this study was to assess the reversibility of pulmonary lesions in Wegener's granulomatosis using serial CT. We reviewed the follow-up CT scans of ten treated patients with confirmed Wegener's granulomatosis. The delay between the first evaluation before treatment and the second, on patients in clinical and biological remission, ranged from 6 to 54 months (mean 20.5 months). Follow-up CT showed a decrease in the extent of disease in all cases. Lesions disappeared completely, without scarring, in 4 of 4 ground-glass opacities, 25 of 36 nodules, and 4 of 9 pulmonary consolidations; they disappeared with residual scarring in 8 of 8 masses, 3 of 9 pulmonary consolidations, and 2 of 36 nodules. The majority of lesions disappear without scarring. Residual fibrosis may follow the occurence of masses and pulmonary consolidation. Computed tomography permits assessment of cicatricial lesions.