Spontaneous abortion is the most common complication in pregnancy. It is considered that 15% of all pregnancies end with spontaneous abortion. More than 50% of those cases are caused by chromosomal abnormalities. Main chromosomal abnormalities are: trisomy, polyploidy and monosomy. The most commonly used tissues for cytogenetic analysis (karyotyping) are coronal villi and skin tissues. Conventional techniques used to cultivate coronal villi and skin tissues are long-term and short-term methods. The basic aim of this study was to determine the incidence of individual chromosomal abnormalities in spontaneous abortion, to compare the success of different tissue cultivation techniques, and to determine possible effect of maternal age to the occurrence of individual chromosomal abnormalities and gestational age of aborted fetus. Analysis of 253 fetuses, showed that the most common causes of spontaneous miscarriagees are chromosome 16, 18 and 22 trisomies and chromosome X monosomy. It was found that there is no correlation of maternal and gestational age of aborted fetus, while maternal age was in positive correlation with the appearance of trisomies. By comparing the success of the cytogenetic analysis of placental tissue and skin tissue, it was found that the placental tissue was better samples for precise cytogenetic analysis and that the long-term method was more successful.