During the years 1984 to 1989, in order to determine of chromosome abnormalities are associated with recurrent spontaneous abortions, cytogenetic studies were performed 384 couples. Abnormal karyotypes were found in 51(13.3%) couples. There was no apparent relation with the number of abortions. The abnormalities were as follows: 17(4.4%) balanced translocation; 15(3.9%) mosaicisms; 17(4.4%) pericentric inversion; 2(0.5%) addition or isochromosome. Chromosome abnormalities were observed in 34(67%) of the wives and 17(33%) of the husbands. In addition, we detected polymorphic variants of chromosomes in 89(23.2%) subjects. Reciprocal translocations(13/17) were more common than the robertsonian type(4/17). All of the mosaicisms were associated with the sex chromosomes in 10 females and 5 males subjects. Pericentric inversions were most common in chromosome 9. Compared to previously studied general populations, significantly higher frequencies of translocations, mosaicisms and inversions were found in couples with repetitive spontaneous abortion. This suggests that couples should have chromosome studies after two or more abortions.