Kinetic experiments were carried out for the sorption of safranin onto rice husk particles. The kinetic data were fitted to pseudo second order model of Ho, Sobkowsk and Czerwinski, Blanachard and Ritchie by linear and non-linear regression method. Non-linear method was found to be a better way of obtaining the parameters involved in the second order rate kinetic expressions. Both linear and non-linear regression showed that the Sobkowsk and Czerwinski and Ritchie's pseudo second order model were the same. Non-linear regression analysis showed that both Blanachard and Ho have similar ideas on the pseudo second order model but with different assumptions. The best fit of experimental data in Ho's pseudo second order expression by linear and non-linear regression method showed that Ho pseudo second order model was a better kinetic expression when compared to other pseudo second order kinetic expressions. (c) 2005 Published by Elsevier Ltd.