The results of 35 amniocentesis, between 13 and 17 weeks of pregnancy are presented. Cytogenetic study was performed in 28 of them. Chromosomic anomalies were detected in 3 cases: A 21-trisomy, a 14/21 translocation with 21-trisomy and a partial trisomy of chromosome 2. The values of alpha-feto protein were measured in 10 cases, and were in normal range. Amniocentesis indications in the early detection of chromosomic anomalis in high risk couples and the interest of alpha-feto protein detection in the prediction of neural-tube defects, are commented.