<b>Aims: </b>The identification of fetal abnormal chromosomes in high risk pregnancies, allows proper pediatric and obstetric management of the cases as well as genetic counseling. The results of 100 genetic amniocentesis from January 2009 to December 2010, since the accreditation of these laboratory tests, are reported. <b>Methods: </b>Amniocentesis were performed in hospitals of the social security system and in private facilities. There were two main reasons for referral: abnormal ultrasound assessment (65% of cases) and advanced maternal age (28%). Fetal cells were flask open cultured and suspension harvested. <b>Results: </b>Abnormal fetal karyotypes were 35%. Success rate for samples of acceptable quality was 100%. Turn around time was 13 days average. This data is in accordance with American and European requirements for quality and competence. The laboratory also participates annually in Cytogenetic European Quality Assessment rounds with achievements of satisfactory performance. <b>Conclusion: </b>In Costa Rica we have skilled and experienced perinatologists as well as highly sophisticated ultrasonographic equipment, so that many fetal and pregnancy abnormalities are routinely detected. In these cases, the fetal karyotype of guaranteed quality is a very useful tool in their adequate clinical management.

accreditation; prenatal diagnosis; cytogenetics; amniocentesis; Costa Rica