A prospective 3-month survey of neonatal respiratory disorders in 17,192 Italian infants born in 65 hospitals, located in 17 Italian regions representative of northern, central and southern Italy, was performed to evaluate the incidence of neonatal acute respiratory disorders and their risk factors. The prematurity rate was 7.3%, while the extremely low birth weight (< 1,000 g) and very low birth weight (< 1,500 g) rates were 0.58% and 0.99%, respectively. Four hundred and ninety-one infants (2.8%) developed respiratory signs. Lethality or specific fatality rate (SFR) for acute respiratory disorders with regard to the overall study population was 0.45%. The male/female ratio of affected infants was 1.3:1. Among affected newborns the case fatality rate (CFR) for respiratory disorders was 15.88% (78/491) and was higher in males than in females (2:1), in infants with a gestational age of < or = 28 weeks (60%) and birth weights of < 1,000 g (50%). Moreover, the SFR was higher (p < 0.05) in the infants of mothers older than 34 years. SFR was 3.0% in intrauterine growth-retarded infants, 3.6% in the first twin and 3.2% in the second twin. An Apgar score of < or = 3 at 5 min was strongly related to the incidence of respiratory disorders (47.1%). The antenatal prevention of neonatal respiratory distress syndrome with maternal corticosteroid treatment was performed in 84% of newborns (< 32 weeks) with respiratory problems in northern Italy, and about 25% and 38% in central and southern Italy, respectively. The CFR was double in southern Italy as compared with northern and central Italy. Prematurity, low birth weight and a low Apgar score (< or = 3) at 1 and 5 min as well as a maternal age of > 34 years are risk factors for acute respiratory disorders.