BACKGROUND: More than half of cancers could be prevented by employing evidence-based interventions (EBIs), including prevention interventions targeting nutrition, physical activity, and tobacco. Federally qualified health centers (FQHCs) are the primary source of patient care for over 30 million Americans - making them an optimal setting for ensuring evidence-based prevention that advances health equity. The aims of this study are to (1) determine the degree to which primary cancer prevention EBIs are being implemented within Massachusetts FQHCs and (2) describe how these EBIs are implemented internally and via community partnerships. METHODS: We used an explanatory sequential mixed methods design to assess the implementation of cancer prevention EBIs. First, we collected 34 quantitative surveys from staff at 16 FQHCs across Massachusetts to determine the frequency of EBI implementation. We followed up with 12 qualitative one-on-one interviews among a sample of staff to understand how the EBIs selected on the survey were implemented. Exploration of contextual influences on implementation and use of partnerships was guided by the Consolidated Framework for Implementation Research (CFIR). Quantitative data were summarized descriptively, and qualitative analyses used reflexive, thematic approaches, beginning deductively with codes from CFIR, then inductively coding additional categories. RESULTS: All FQHCs indicated they offered clinic-based tobacco interventions, such as clinician-delivered screening practices and prescription of tobacco cessation medications. Quitline interventions and some diet/physical activity EBIs were available at all FQHCs, but staff perceptions of penetration were low. Only 38% of FQHCs offered group tobacco cessation counseling and 63% referred patients to mobile phone-based cessation interventions. We found multilevel factors influenced implementation across intervention types - including the complexity of intervention trainings, available time and staffing, motivation of clinicians, funding, and external policies and incentives. While partnerships were described as valuable, only one FQHC reported using clinical-community linkages for primary cancer prevention EBIs. CONCLUSIONS: Adoption of primary prevention EBIs in Massachusetts FQHCs is relatively high, but stable staffing and funding are required to successfully reach all eligible patients. FQHC staff are enthusiastic about the potential of community partnerships to foster improved implementation-providing training and support to build these relationships will be key to fulfilling that promise.