Some deficiencies are clearly recognized with the present system of prenatal genetic diagnosis. It is, at present, restricted only to the second trimester. The methods used are attendant with a risk factor, however small, of fetal death or abortion. Amniocentesis cannot be performed until the 16th week of pregnancy with an additional 2 weeks required for cell culture and analysis forcing a possible elective abortion decision in the midtrimester at the earliest. Termination of pregnancy at this late stage can be complicated by medical and psychological problems. To remedy these drawbacks, many procedures have been developed to obtain and process chorionic villi during the first trimester of pregnancy. In this paper, we will attempt to evaluated different approaches to villi biopsy and an innovative direct method of karyotyping fetal cells which does not require any time for culture at all. The study population consisted of 63 gravid women between 5~12 weeks of gestation. The techniques utilized were blind aspiration and real time ultrasound guided aspiration biopsy. Cytogenetic studies were analyzed by direct chromosome preparations which gave a sufficient number of good quality metaphases, and fetal karyotype was defined within a few hours from chorionic villi biopsy. The results were as follows: 1. In chorionic villi biopsy 21 of 32 women (65.6%) successfully underwent blind aspiration while 25 of 31 women(80.6%) successfully underwent real-time ultrasound guided aspiration. 2. The success rate of chorionic villi biopsy was significantly higher in those with greater than 8 weeks of gestation. 3. Amniotic sac perforation and vaginal bleeding occurred in 2 cases and 5 cases respectively of those undergoing blind aspiration. The same complications occurred in 1 case and 2 cases respectively of those undergoing real-time ultrasound guided biopsy. 4. The chromosome constitution was male in 28 cases and female in 18 cases among which 1 female demonstrated trisomy 21 (Down`s syndrome).