Given to the significant role of enterprise resource planning systems (ERP) in the current organizations, several studies have been accomplished regarding these systems. The Main reason for the present research is having a small share in enhancement of success rate of ERP systems implementation through an applied study. In this study two purposes are pursued. First, this article intends to determine the most important skills required by key users (Also called power users and super users.) of ERP system as one of the most major members of ERP implementation team. Another purpose is to examine the skills shortages of these users in organizations under study and both of these purposes are obtained based on a comprehensive model. This research includes two major parts. First, based on experts' opinion, a model is developed to determine and measure required technical, human, and conceptual skills as well as skills shortages of those involved in ERP implementation such as key users. Then, in second part, based on the above model and by means of a field study and studying thirteen Iranian organizations, the desirable amount (Amount of skill that key users expected to have.) and existing amount (Amount of skill that key users have at present.) of skills of key users are measured in each one of the technical, human, and conceptual categories. Then in order to determine and evaluate skill shortages, the difference between these two amounts in each category is examined. In this paper, human and conceptual skills are determined as the most important skills of key users in ERP implementation. Also, results confirm that key users have skills shortages in three kinds of main skills (i.e., technical, human, and conceptual) in the organizations under study. Moreover, key users in large companies suffer more from skills shortages than ones in SMEs.