One hundred and three patients suffering from systemic sclerosis (SSc), with different extent of skin involvement, were retrospectively examined to investigate the correlations between clinical manifestations and anticardiolipin antibodies (aCL). aCL of IgG, IgA, and IgM classes were measured in the patients' sera by enzyme linked immunosorbent assay. aCL were found in 26 patients (25.2%). A significant association was found between aCL and myocardial ischaemia or necrosis (p = 0.011). No patient showed the clinical picture of the antiphospholipid syndrome. On the basis of clinical manifestations, a protocol for disease score was drawn. Patients with IgG-aCL and with IgA-aCL showed a disease score higher than aCL negative patients (p = 0.008 and p = 0.022 respectively). Thus, the finding of aCL can be considered a useful serological index for the most severe forms of SSc.