Flexibility is a desired quality of software processes. Process flexibility implies a capability to adapt to new contexts. Another aspect of flexibility is the cost of maintaining process effectiveness as new situations arise. A lack of preparedness for future events may constitute a high risk to a software development organization. This paper presents a method for assessing the flexibility of an organization and its processes. The assessment method is scenario-based and provides an estimate of process flexibility in terms of risk. The method is evaluated in a case study, where the process flexibility at a telecommunication software developer has been assessed. The case study indicates that the method is feasible and effective, and that the cost of conducting scenario-based process flexibility assessment is reasonable. The proposed method was able to identify a number of relevant areas to be improved in order to reduce risks of inflexibility for the particular process.