The packaging of deoxyribonucleic acid (DNA) into chromatin within the eukaryotic nucleus can affect processes such as DNA replication, transcription, recombination, and repair. Therefore, studies aimed at understanding at the molecular level how these processes are operating have to take into account the chromatin context. We present a method to assemble DNA into chromatin by nuclear microinjection intoXenopusoocytes. This method allows in vivo chromatin formation in a nuclear environment. We provide the experimental procedures for oocyte preparation, DNA injection, and analysis of the assembled chromatin.