Implementing complex and yet sound and effective accounting information systems known as enterprise resource planning systems, is an enormous project for the firms that want to streamline their information flow and increase their value. As the effects of these systems on the performance of the entities are both financial and non-financial, their success is of crucial importance. This study is an exploratory factorial analysis to identify the factors of successful implementation of ERP systems in the medium and big companies in Albania. We use in depth surveys and interviews with firms that have implemented enterprise resource planning systems and include twenty initial variables in the survey. Later these variables are combined in three factors that have the biggest impact on the success rate of ERP implementation: the overall quality and end-user satisfaction with the ERP system; the cost-benefit ratio of the ERP and the support from the ERP provider and ERP implementing consultant. This study contributes not only theoretically to the empirical literature, but also practically because it helps businesses of the region that are considering implementing ERPs in the future to pay attention to the most critical factors of success with ERPs.