The purpose of this article is to describe a method for converting practice guidelines to measurement criteria. To evaluate the processes of care received by patients with stroke at 11 Veteran's Administration hospital sites, we developed a measurement system based on Agency for Health Care Policy and Research (AHCPR) Post-Stroke Rehabilitation Clinical Practice Guidelines. Guideline recommendations were used as the framework for identifying important dimensions of care, and for developing chart abstraction instruments for both the acute and postacute settings. Using a modified Delphi technique to solicit opinions from an expert panel, a method was developed for aggregation of item-level chart abstraction components to overall guideline compliance scores. The measurement system was shown to have good-to-excellent intrarater and interrater reliability at the item, dimension, and overall compliance score levels. Abstraction of a sample of 100 medical records demonstrated the ability of the instruments to detect variability in processes of post-stroke care. This study provides the foundation for future research, which will evaluate associations between processes of post-stroke care, as measured by this medical chart abstraction system, and patient outcomes. (All abstraction instruments, criteria, and scoring algorithms described in this article are available for download at http://www2.kumc.edu/coa.)