Chromosomal DNA in E.coli with about 5 million base pairs, has only more than 1 mm in length so that in comparison with the size of living cells, this molecule has to be intensively compacted. The initial process of bacterial genomic packaging is accomplished by polyamines including spermin and sper-midin. In addition, several bacterial of protein molecules with its small size called histone-like proteins cause folding in the highly compacted structure. Some of the histone-like proteins in bacteria have been known including: HU, IHF, H-NS, HLPI, H and FIS. They have similarity to each other in general but play different roles and different structural criteria. These include their roles in initiation of replication, control and regulation of transcription (as an activator or repressor), and in site-specific recombination.