Many studies have addressed critical success factors in ERP implementation. However, none of them have addressed the reinforcement phase in which new behavioural routines are refrozen. In addition, there are few studies that have focused on ERP implementation and critical success factors in developing countries. In this research, the same methodology was used to examine reinforcement and critical success factors in developed countries and in Brazil as a developing country. It was found that significant attention was not put on the examined reinforcing factors except for training and employee information exchange. Training was found to be a key factor in successful ERP implementation and it was related to the scope of the project as well as to financial constraints. Top management support was confirmed as the important success factor and it was found to be greater when the scope of the project was larger to avoid the risk of project failure. The lack of managerial engagement, especially regarding planning and change management, was found to be the most important problem area, along with the quality of project leadership. These factors could therefore also be considered critical success factors. In addition, even though communication was found to be of huge importance, it was not without problems, which was found to be related to the project scope and poor level of expertise on the part of management. That is why consultant engagement and support was found to be the most important success factor in ERP implementation. Future studies could take a more nuanced approach and include more exploratory variables, especially by implementing the case study methodology(1).