Background MedsCheck is an in-pharmacy medication review program funded by the Australian Government. It is intended to improve patient understanding of medicines and resolve adherence issues. Objective To explore MedsCheck from the community pharmacists' perspective, focusing on the perceived effectiveness of the program, barriers to its optimal delivery, and the integration with other services. Setting Individual interviews in one territory and a national online survey of Australian community pharmacists. Method Using a mixed-method triangulation design, the interviews and the survey were conducted concurrently. The interviews were semi-structured, transcribed verbatim and thematically analysed. The survey, comprising closed and open-ended questions, was quantitatively and thematically analysed. The findings were first analysed separately and finally integrated by searching for convergence, complementarity, and discrepancy. Main outcome measure Pharmacists' perceptions of the effectiveness and barriers of MedsCheck. Results Eight interviews were conducted, and 232 survey responses collected. In the interviews, themes related to perceived benefits (appreciation, reduced confusion, and strengthening relationships), barriers (lack of controls, lack of staff, lack of awareness, and lack of understanding of scope of services), and the integration with other services (strong link with dose administration aids) emerged, which mostly correlated with the survey's results. Ten percent of surveyed respondents did not provide the MedsCheck service; their main reason being insufficient staffing. Of the pharmacists offering the service, 76% strongly agreed that patients were benefitting. MedsCheck reviews were usually initiated by pharmacy staff. Fifty-three percent of respondent pharmacists never or only sometimes reported the review outcomes to the patient's general practitioner. Conclusion The pharmacists believed that MedsCheck is useful to improve patients' understanding and management of their medicines. However, there are currently barriers to the effective delivery of the service, including workload issues, lack of patient awareness, and the service's integration with the broader care of the patient. If these were appropriately addressed, the in-pharmacy medication review program could help pharmacists to better engage with patients and general practitioners and enhance understanding of medication and adherence.