Today, enterprise resource planning system (ERP) becomes popular and it is implemented in most business (in all fields and sizes) all over the world as well as in Vietnam. However, according to consultant experts, ERP projects, though on a large scale with high cost, entail low success rate. For Vietnamese contexts, those findings above are all the more true, because most of Vietnamese enterprises are on a small scale with short-time computerization access, lack of understanding of enterprise systems, and lack of financial resources. This research focuses on exploring key factors affecting the success of ERP projects in Vietnam. Through case studies and data collection, using SPSS for data analysis, key factors affecting the success of ERP projects are listed on such a descending order as follows: Characteristics of ERP team, Quality of consultancy, Characteristics of end-users and Characteristics of business. From the abovementioned analysis, suggestions for ensuring success of ERPs in Vietnam are also proposed.