In ERP implementation, customization should usually be undertaken to ensure a fit between business process systems and current organizational processes. This paper focuses on the issues associated with ERP customization and how large organizations deal with them. Information presented in this paper was gathered from reviewing related literature and interviews with implementation and consulting teams of a major ERP vendor. Customization issues addressed in this paper are organizational information needs or requirements, cost, technical complications, and lack of knowledge and experience within the implementation team. These factors, if not considered adequately, may lead to ERP implementation failure.