Scenario uses have become popular in various fields such as interface design, requirement engineering, and usability evaluation. Although scenarios can help design and evaluation by describing possible ways to accomplish relevant tasks using given interfaces, there are few formal systematic methods to compose the most desirable set of scenarios for design or evaluation. For efficient and effective usability evaluation, it is necessary to select and organize scenarios so that the included tasks contain all important procedures and interface controls without too much redundancy. This article proposes a scenario elicitation method based on operation sequence patterns. A worked example is provided for illustration.