A major factor in the decision to develop enterprise software applications is the size of the project, which determines the amount of work necessary, which in turn will give decision makers some idea about the time required and the estimated cost. Two of the major approaches for such estimation—the Use Case Points (UCP) and COSMIC-FFP methods – are compared in this paper. The accuracy and reliability of each method are evaluated through the measurement of 50 use case studies. These were collected from the Customer Relationship Management systems development project of a major enterprise service institution. The results show that the UCP method is more accurate and reliable than the COSMIC-FFP in determining work effort.