As for the recent PM regulations, a diesel particulate filter (DPF) has been one of the important after-treatment technologies. Although the square cell structure of DPF is a generally worldwide standard, several cell designs have been proposed to reduce the pressure loss due to the soot loading as well as the ash deposition in DPF. In this study, we focused on the cell geometry using a hexagonal cell DPF and a conventional square cell DPF. In the engine test bench under nearly real conditions, these DPF performances were evaluated. Results show that, in comparison with square cell DPF, the particle number concentration of the hexagonal cell DPF decreases more rapidly, and the filtration efficiency is higher. In addition, in DPF regeneration test, independent of the inlet temperature, the regeneration rate of the hexagonal cell DPF is higher. Between two DPFs, the aperture ratio of inlet/outlet cells is different. Thus, the superior DPF performance of the hexagonal cell DPF could be explained by the difference of exhaust gas flow and soot deposition region. (C) 2012 Elsevier Ltd. All rights reserved.