In the last decade, chorionic villi sampling (CVS) has been widely accepted as a new technique in prenatal diagnosis. An inconsistency in karyotypes between CVS and fetal tissue was found in clinical practice, although the chorionic villi and the fetal tissues were from the same fertilized ovum. Karyotypes from direct chromosomal preparation of chorionic villi and cultured fetal tissues in 52 artificial abortion samples were compared. Results showed two cases with karyotypic inconsistency: (1) 46, XX/46, XY in the chorionic villus direct preparation and 46, XX in the fetal tissue; (2) 46, XY in the direct preparation of chorionic villi and 45,XY, t (15q21q) de novo in the fetal tissue. Our research demonstrates that karyotype from chorionic villus direct preparation does not always reflect the fetal karyotype.