Pleuro-pulmonary involvement has been well recognized in adults affected with systemic lupus erythematosus (SLE), but few studies have been carried out in children. A longitudinal study on a group of 15 children affected with juvenile SLE (JSLE), asymptomatic for lung disease, was performed, and the prevalence and the features of respiratory function alterations, over a period of 12 months, were analysed. Moreover, a possible correlation between any pulmonary function test (PFT) and disease duration, disease activity, visceral involvement and immunological pattern was evaluated. At baseline, a significant functional lung impairment was present in 40% of patients, with a significantly reduced FVC, VA and DLCO in 26% of them; in 60% of patients at 6 months and in 33% of patients at 12 months. At 6 and 12 months, our data did not show any significant modification in PFTs and the restrictive pattern, observed at baseline, remained unchanged. No correlation between altered PFTs and disease duration, activity and/or immunological findings was found. At baseline, the presence of neurological involvement was the only extra-pulmonary feature correlated to reduced FVC.