BackgroundWomen Veterans with co-morbid medical and mental health conditions face persistent barriers accessing high-quality health care. Evidence-based quality improvement (EBQI) offers a systematic approach to implementing new care models that can address care gaps for women Veterans.ObjectiveThis study examines factors associated with the successful deployment of EBQI within integrated health systems to improve primary care for women Veterans with complex mental health needs.DesignFollowing a 12-site (8 EBQI, 4 control) cluster randomized study to evaluate EBQI effectiveness, we conducted an in-depth case study analysis of one women’s health clinic that used EBQI to improve integrated primary care–mental health services for women Veterans.ParticipantsOur study sample included providers, program managers, and clinic staff at a women Veteran’s health clinic that, at the time of the study, had one Primary Care and Mental Health Integration team and one women’s health primary care provider serving 800 women. We analyzed interviews conducted 12 months, 24 months, and 4 years post-implementation and call summaries between the clinic and support team.Main MeasuresWe conducted qualitative thematic analysis of interview and call summary data to identify EBQI elements, clinic characteristics, and reported challenges and successes within project development and execution.Key ResultsThe clinic harnessed core EBQI elements (multi-level stakeholder engagement, data-driven progress-monitoring, PDSA cycles, sharing results) to accomplish pre-defined project goals, strengthen inter-disciplinary partnerships, and bolster team confidence. Clinic characteristics that facilitated implementation success included prior QI experience and an organizational culture responsive to innovation, while lack of pre-existing guidelines and limited access to centralized databases posed implementation challenges.ConclusionsSuccessful practice transformation emerges through the interaction of evidence-based methods and site-specific characteristics. Examining how clinic characteristics support or impede EBQI adaptation can facilitate efforts to improve care within integrated health systems.