Ninety-one patients with progressive systemic sclerosis have been examined both clinically and serologically in order to have a better prognostic insight. Three main serological profiles have been isolated. The patients with anticentromere antibodies (ACA) represented one third of the cases, developed skin sclerosis rather later and rarely exhibited ankyloses and ulcerations. The esophagus was commonly involved while the lung, heart and kidneys were not. ACA-positive patients were not identified with the CREST syndrome, as the latter disclosed other profiles with the same frequency. Patients with anti-Scl-70 antibody represented one fourth of the cases and had the fastest progression, developing sclerosis in less than 5 years after the onset of Raynaud's phenomenon. Ankyloses and lung fibrosis, as well as joint, heart and kidney involvement, were found in most of them. Patients with anti-SSA/Ro antibodies were uncommon, but corresponded to a severe subset, having a fast progression and a constant involvement of the lung. Probably due to the rougher definition of their serology, patients with antinuclear, antispeckle-patterned and anti-Ku antibodies or without any detectable antibody could be defined less easily and corresponded to an intermediate position between ACA- and anti-Scl-70-positive patients. Though it is probably premature to trust it completely, a serological classification may provide the prognostic clues clinical classifications cannot.