General PCR technique alone has a limitation for preimplantation genetic diagnosis(PGD) using single blastomere. Recntly developed primer extension preamplification(PEP) technology amplifies the whole genome and thus, simultaneous multiple locus analysis became possible. In this study, we report the efficacy of PEP-PCR for PGD in three muscular dystrophy carriers undergoing IVF-ET. A total of 37 blastomeres were obtained from 40 embryos at six to eight cell stage in three IVF cycles in two DMD and one BMD carriers. Whole genome from single blastomeres were amplified using I5-base oligonucleotide random primers. PCR amplified products of exon 45 in the dystrophin gene and alphoid X/Y loci for gender determination were analysed by 2% metaphor gel electrophoresis. A total of 37 PEP-PCR replicates from 37 single blastomeres from 40 embryos and 37 blanks were performed. We obtained the reliable results for exon 45 and alphoid X/Y. Transfer of female embryos and unaffected male embryo was attempted in three couples. Unfortunately, pregnancy was not achieved in these cases. PEP-PCR is a reliable and efficient PGD method in multiple locus analysis using single blastomere.