ASOG is one of the group contribution methods for predicting activity coefficients. This article deals with the determination of ASOG group interaction parameters for 20 group pairs in order to extend and revise the existing parameter matrix. In particular, all group interaction parameters relating to the NMP group have been revised and extended. The group interaction parameters relating to the C=C (C-C triple bond group) have also been revised. The data base used for determining the parameters are the vapor-liquid equilibria (VLE) and infinite-dilution activity coefficients (gamma(infinity)) stored in the Dortmund Data Bank.