It is critical to manage risks to complete IS(Information Systems) projects successfully. Identifying risk factors would be the first step for the project risk management. Previous research has discussed the issue with various points of view, such as different risk factors based on project types and roles involved in their projects. This paper empirically explored how people perceive different risk factors by project development methodology, between self-developing IS using programming language like C, Visual Basic and adapting software package already developed by software venders like ERP, CRM packages. There are researches regarding project risk factors for project management in the several point of views. And there are also researches regarding comparison between self-developing and adapting software packages methodology in IS project. However, there are no study on project risk factors comparison between self-developing IS using programming language and adapting software packages already developed by software venders in IS project. This research can be differentiated from previous ones, because it was considered both point of project risk management and development methodology in IS project. This research results implied meaningful messages to enterprise company to be planned IS projects and people who involved in IS projects. They should consider and need to prepare differently according to each development methodology for preventing project risks. It makes them reduce project risks in each case and complete successfully IS projects. Especially, if they have no experiences for implementing software packages, they can forecast the project risks and prepare them in advance.