A deoxidized low-phosphorous copper (DLPC) was processed by accumulative roll-bonding (ARB). The evolution of nano-grains in DLPC with the ARB was investigated by TEM and EBSD analysis. TEM observation revealed that the ultrafine grains equiaxed to ND and elongated to RD developed in the sample after 8-cycle ARB. In addition, it was found that the mean spacing of grain boundaries, which was 45 microm in initial material, reduced to 5.2 microm after 1 cycle, 650 nm after 3 cycles, 510 nm after 5 cycles, and then surprisingly 190 nm after 8 cycles, respectively. In addition, the fraction of high-angle boundaries in the sample after 1-cycle ARB was 0.22, but it after 8-cycle ARB was surprisingly 0.70. Therefore, it is concluded that the ARB is a very effective process for development of ultrafine grains in case of DLPC as well.