This article describes how integrated health information technology affects the collection and flow of client-level intake and assessment data within substance abuse treatment agencies. We combined process mapping and qualitative inquiry methods to analyze staff interviews (N = 54) from eight agencies in four U.S. states. Integrated health information technology was related to expedited and improved flow of information, while nonintegrated health information technology systems were associated with double data entry, multiple eligibility screenings, and different intake processes across levels of care. Process mapping is an effective tool to identify barriers to efficient client-level data management and opportunities to leverage health information technology to streamline the intake process of substance abuse treatment agencies, improve staff productivity, and enhance the accuracy and information flow.