DTPA is a popular chelating agent used during the hydrogen per- oxide bleaching of pulp. In the present work, DTPA was used instead of chitosan during the hydrogen peroxide bleaching of CTMP. The results showed that the brightness of the bleached pulp slightly increased by 0.5% ISO compared to that of the control when 0.2% DTPA was added. This brightness was lower than that obtained when 0.1% chitosan was added during hydrogen peroxide bleach- ing. Moreover, the residual hydrogen peroxide content increased to 35% when 0.2% DTPA was added, which was much higher than the values observed for the control and for the case in which chitosan was added. So the higher residual hydrogen peroxide concentra- tion after peroxide bleaching of the pulp did not signify the higher bleaching efficiency.