The overall IT investments made by a firm can be viewed as a portfolio. One challenging decision thus is the selection of a superior IT portfolio. The main proposal of this dissertation is that the characteristics of IT project investment could influence the quality of IT portfolio choice. The methodology of this dissertation is primarily based on the simulation modeling methodology. This dissertation develops the approaches to characterizing a set of candidate IT project investments and simulating these characteristics. In addition, this dissertation develops the models to select the optimal IT portfolio choice. The first chapter in this dissertation investigates the selection characteristics of IT project investment: The second chapter in this dissertation investigates the value characteristics of IT project investment.