Human genomics research has produced vast amounts of data that can be applied to or used to inform pharmacogenomic studies. The Internet is an extremely useful resource for pharmacogenomics as many Web sites provide access to data from genomic and clinical studies or host tools which can be used to interpret findings or generate hypotheses. Human genetic variation can now easily be explored or visualized through genome browsers and Web-based repositories which store the details of millions of human germ-line and somatic genetic variants. Gene expression data from many different tissue and cell types are available through Web-based repositories, and human genetic variants that associate with mRNA expression can be identified using Web data portals. Pharmacogenetic associations can be explored through publically available data repositories and the functionality of genetic variants predicted through Web-based bioinformatic tools. Furthermore, resources relating to currently used genetic tests are available online. Large clinical and population studies, many linked to medical records, can be queried for the availability of biospecimens or data. In the future, as the amount of genomic and associated clinical data increases, there is little doubt that Web-based resources will continue to evolve and overcome barriers hindering their efficient use, leading to systems-based approaches to pharmacogenomics.