Comprehensive understanding of regulation mechanisms of biological phenomena mediated by functions of genomic DNA requires identification of molecules bound to genomic regions of interest in vivo. However, nonbiased methods to identify molecules bound to specific genomic loci in vivo are limited. To perform biochemical and molecular biological analysis of specific genomic regions, we developed the insertional chromatin immunoprecipitation (iChIP) technology to purify the genomic regions of interest. We applied iChIP to direct identification of components of insulator complexes, which function as boundaries of chromatin domain, showing that it is feasible to directly identify proteins and RNA bound to a specific genomic region in vivo by using iChIP. In addition, recently, we succeeded in identifying proteins and genomic regions interacting with a single copy endogenous locus. In this paper, we will discuss the application of iChIP to epigenetics and chromatin research.