We studied the clinical features and autoantibody profile in 21 patients with antisynthetase syndrome (AS) comparing to 48 patients with classical polymyositis and dermatomyositis without AS. At presentation, the AS group showed more frequently the presence of interstitial lung disease (ILD), arthritis/arthralgia, mechanic's hand and anti-Ro/SSA antibodies. Patients without AS had more frequent proximal weakness and cutaneous erythematosus rash. Interestingly, the AS patients with associated anti-Ro/SS-A antibodies seem to be predisposed to the development of a more severe ILD, expressed as HRCT total score > or = 7. During a follow up of about 3 years (range 6-110 months), the presence of anti-Jo-1 antibody alone or in association with anti-Ro/SSA did not influence survival or a more severe prognosis of ILD.