The data dictionary system is a documentation source that is useful for management reviews of existing and proposed systems, EDP audits, and system development functions. Early data dictionary systems had limitations that reduced their effectiveness and contributed to their limited usage. Many of these limitations have been or are being resolved with the result that evolving data dictionary systems offer many benefits to management and EDP auditors. This article evaluates the features, potential benefits, and limitations of data dictionary systems from the perspective of the EDP auditor.