The aim of this study was to estimate the incidence of complications due to the prenatal invasive diagnosis performed by amniocentesis at the Department of Prenatal Diagnosis of the Second University of Naples.A total of 1.580 patients who underwent amniocentesis from January 2001 to December 2003, were submitted to a telephone interview concerning the complications that occurred after the invasive diagnosis.Only 1.416 patients out of the total patients interviewed answered correctly to the questionnaire. The complications that occurred in the first 24 h from amniocentesis (early complications) included light contractions and lipothymia respectively in 8.3% and 6.7% of cases; losses of amniotic fluid took place in 1.06% while bleedings were observed in 0.85% of cases. The incidence of abortions occurred in the week following amniocentesis was 0.78%. Preterm labor occurred in only 6% of the patients submitted to amniocentesis, spontaneous labor at term in 43% and cesarean section in 51%. The Apgar index at birth was normal in 95.7% of cases. In the remaining 4.3% pathologies like hypoglycemia or respiratory distress, which promptly regressed, were observed. Early complications and the incidence of abortions were significantly and independently associated with the double needle puncture but not with maternal age or the placenta specimen obtained during amniocentesis.A careful observation of the technique and the protocol, as well as a careful selection of patients are necessary presuppositions in order to further decrease the occurrence of complications due to amniocentesis.