This work presents the results of a study of kinetic and adsorption isotherms of a cationic polyamine on bleached pulp of sugar cane bagasse. Polyamine was synthesized at laboratory scale and used in an experimental trial for the production of wet strength paper. In the isotherms and kinetic adsorption studies, pulp dispersions were used with the addition of KCl or aluminum sulfate. The concentration of the unadsorbed polyamine was determined by the polyelectrolyte titration. It was found that the polyamine adsorption in KCl at different pH values, and in the presence of Al3+, shows adsorption isotherms of the high affinity solute-adsorbent type, which satisfactorily adjust to the Langmuir adsorption isotherm equation. In systems in the presence of KCl, the polyamine adsorption is approximately four times higher than in the presence of aluminum sulfate. The speed constants of the fast stages are higher than the slow ones.