Characterizing the state of software engineering practice within an organization is a necessary prerequisite to orderly, meaningful, and sustainable improvement of the organization’s ability to produce or support cost-effective, high quality software products. The Software Engineering Institute (SEI) is developing a methodology for conducting SEI-assisted assessments of software engineering capability. The assessment methodology has five phases: 1) selecting the candidate organization, 2) preparing for the assessment, 3) conducting the assessment, 4) communicating final assessment findings and action recommendations, and 5) post-assessment followup activities. This report describes the methodology in detail.