The severe plastic deformation (SPD) of metallic materials has become attractive in recent years. Accumulative roll bonding (ARB) is a SPD process that can impose deformation to a sheet metal, as it develops fine grains of typically submicrometer or even the nanometer level in polycrystalline materials. The purpose of the present study is investigation of microstructural evolution and micro hardness behavior of the commercial purity Aluminium (AA1050) severely deformed by the ARB process. The microstructural evolution during 13 cycles of ARB process was investigated. With increasing ARB cycles the grains size reduced in nanometer range. Furthermore, Micro-Vickers hardness measurement was carried out throughout thickness of the ARB processed sheets.