IGG is an open-source Java package with graphic interface to efficiently and consistently integrate genotypes across high throughput genotyping platforms (e.g., Affymetrix and Illumina), the HapMap genotype repository (http://www.hapmap.org/), and even genotypes from the collaborators’ projects. It is equipped with a series of functions to control qualities of genotype integration and to flexibly export genotypes for genetic studies as well.