To evaluate the coexistence of additional autoimmune disease in a population of patients suffering from systemic sclerosis. The record-charts of 118 Italian patients affected by systemic sclerosis (12 men, 106 women, mean age of 57.2 years, mean duration of disease 8.7 years) followed by a single centre were reviewed; any other diagnose of autoimmune disease the patient was given was recorded. Thirty-eight scleroderma patients (32.2%) were affected by one or two concomitant autoimmune diseases, for a total of 42 diagnoses. The most represented associated autoimmune diseases were autoimmune thyroiditis (17 cases) and primary Sjögren's syndrome (10 cases). Both pulmonary fibrosis as diagnosed by chest X-ray and the extension of skin involvement evaluated by Rodnan total skin score were not correlated with an increased incidence of an additional autoimmune disorder. Our study shows that approximately one third of patients affected by systemic sclerosis developed one or more additional autoimmune diseases. Therefore patients with systemic sclerosis should be carefully evaluated both at onset and during the follow-up for the possible coexistence of other autoimmune disorders.