Pepper (Capsicum spp.) germplasm shows diverse phenotypic variations including fruit size, color, pungency, and many other horticultural traits. Traditional markers including SSR, AFLP, and RFLP have been used to construct genetic maps using biparental populations. However to assess the genetic diversity of large number of germplasm, a robust and rapid marker development and genotyping approach is needed. We used six pepper accessions including C. annuum, C. chinense, C. baccatum and C. frutescens and performed genotyping-by-sequencing (GBS). To select the most appropriate condition, eight different 2 bp selective nucleotides were used to make GBS libraries. Selective nucleotide ‘OO’ showed the largest number of reads in all samples, and 11,026 to 47,957 high-quality SNPs were called in six accessions. When C. annuum ‘CM334’ genome sequence was used as a reference, C. annuum showed the smallest number of SNPs, while C. baccatum which was known to be a different Capsicum clade showed the largest number of SNPs. Pepper core collection chosen to represent the genetic diversity of whole germplasm will be genotyped by high-density SNPs developed from GBS. We will perform genome-wide association study (GWAS) using genetic and phenotypic variation to identify the functional genetic loci controlling horticultural traits.