Measurement-based care (MBC) in behavioral health involves the repeated collection of patient-reported data that is used to track progress, inform care, and engage patients in shared decision making about their treatment. Research suggests that MBC increases the quality and effectiveness of mental health care. However, there can be challenges to implementing MBC, such as time burden, lack of resources to support MBC, and clinician attitudes. The Veterans Health Administration (VHA) is currently undertaking a multiphase MBC roll-out, the first phase of which included 59 sites across the country. The present study examined implementation of this initiative in an effort to learn more about the process of implementation, including best practices, challenges, and innovations. Semistructured interviews were conducted with 20 MBC site champions and 60 staff members from 25 VHA medical centers across the country. Qualitative data analysis was conducted to identify key themes related to MBC implementation. Results were described for 3 components of MBC implementation: preparing for implementation, administering measures, and using and sharing data. Training and staff buy-in were key to the preparation phase. Staff members reported a variety of methods and frequencies for the collection of MBC data, with many staff members identifying a need to streamline the collection process. Staff members reported using data to track progress and adjust treatment with patients. Efforts to use data on a programmatic level were identified as a next step. Innovative solutions across clinics and sites are described in an effort to inform future MBC implementation, both within and outside of VHA. (PsycInfo Database Record (c) 2020 APA, all rights reserved).