Quantitative fluorescent PCR (QF-PCR) has been used by many laboratories for prenatal diagnosis of the most common aneuploidies. QF-PCR is rapid, cost-effective, and suitable for automation and can detect most abnormalities diagnosed by conventional karyotyping. Whether QF-PCR should be used alone in most of the samples and in which karyotyping should also be offered is currently a topic of debate. We evaluated and compared the results obtained from 7679 prenatal samples in which conventional karyotype and QF-PCR had been performed, including 1243 chorionic villi and 6436 amniotic fluid samples. Concordant QF-PCR and karyotype results were obtained in 98.75% of the samples. An abnormal karyotype associated with adverse clinical outcome undetected by QF-PCR was found in 0.05% of samples. Therefore, QF-PCR can be used alone in a large number of samples studied in a prenatal laboratory, thereby reducing both the workload in cytogenetic laboratories and parental anxiety when awaiting results.