AbstractRisk planning requires an organization global view, as it is strongly centered in the experience and knowledge acquired in former projects. The larger the experience of the project manager the better will be his ability in identifying risks, estimating their occurrence likelihood and impact, and defining the mitigation and contingency plans. However, project manager risk knowledge cannot stay in an individual level, but it must be made available to the organization. This paper describes an approach to risk planning in software projects based on the organizational risk knowledge reuse. A risk management process focused on the capture and utilization of organizational knowledge together with a support case tool make part of this approach. An experimental study of the relations between risk-causing facts and risks of software projects was accomplished and its results used to define such a tool.