Abstract. This paper aims at carrying out business process modelling and business process improvement using TAD methodology. The methodology consists of six phases; the first three deal with business process modelling and improvement, and the last three phases continue with the implementation of the improved business processes by developing an information system, which covers the areas discussed. To make the methodology capable of carrying out business process modelling and improvement, the first three phases of the methodology are intended to solve this problem successfully. The problem of Sales_Claim is used as an example to show the implementation of the new concepts of the methodology. The results of this work are very encouraging.