Abstract: In this study a method was presented for prioritizing information systems implementation consisting of an evaluation process method and a graph representation model. The method was supported by graphs amalgamation. Two independent graphs were constructed to order the information systems applications. A graph was constructed using a partial order relation from the business/organizational point of view and the other graph was built using a partial order relation from information technology strategic point of view. A new graph that incorporates the most general properties was constructed under the reflexive-transitive closure of both partial ordering relations. Partial ordering relations were implemented by priority functions defined by features that were mostly qualitative: classes, factors, sub-factors, attributes and metrics. To represent the prioritization order proposed a 4×4 matrix chart. The method produces a priority order of the information systems that responds appropriately to the dynamic changes of the business strategy of an organization. This method outlines how a planning model for the automation of the organization must be developed. The prioritization method was supported by an Information Technology Strategic Planning (ITSP) model and methodology. The aim of this study was to validate the ITSP model. The prioritization method was presented under a formal treatment and illustrated with a case study constructed at a non-profit organization.