The Human Genome Project was completed in 2003. A catalog of common genetic variants in humans was built at the International HapMap Project. These variants, known as single nucleotide polymorphisms (SNPs), occur in human DNA and distributed among populations in different parts of the world. By using the Linkage Disequilibrium and mapping blocks are able to define quantitative characters of inherited diseases. Currently 50 K-5.0 M microarray are available commercially, which based on the results of following the ENCODE & 1000 genome projects. Therefore the genome wide association study (GWAS) has become a key tool for discovering variants that contribute to human diseases and provide maximum coverage of the genome, in contrast to the traditional approach in which only a few candidates genes was targeted. The available public GWAS databases provided valuable biological insights and new discovery for many common diseases, due to the availability of low cost microarray. The GWAS has the potential to provide a solution for the lack of new drug targets and reducing drug failure due to adverse drug reactions either. These are critical issues for pharmaceutical companies. Here, the Japan PGx Data Science Consortium (JPDSC), which was established on February 20, 2009 by six leading pharmaceutical companies in Japan, was introduced. We believe that the efforts of stakeholders including the regulatory authorities, health providers, and pharmaceutical companies to understand the potential and ethical risk of using genetic information including GWAS will bring benefits to patients in the future.