Objective: Describe and discuss the use of action research in the Pharmaceutical Assistance restructuring of primary care in the city of Lagoa Santa/MG (Brazil), for the implementation of comprehensive medication management services.Methods: An action research project, based on fortnightly thematic discussions with a group of ten pharmacists, was used as a management tool to foster the engagement and critical reflection of pharmacists involved in the construction of their clinical practice in primary care.Results: Action research encouraged pharmacists to think about their practices and to perceive the need for a clearer definition of their roles and responsibilities in primary care. The collective development allowed pharmacists to recognise their weaknesses and strengths, identifying themselves as professionals capable of assuming co-responsibility for the pharmacotherapy of the patient. The re-organization of the service was necessary to provide support for actions related to the logistic of medicines, so pharmacists could dedicate time to their clinical practice. Conclusion:Action research can be an effective instrument of reflection, motivation and empowerment for the pharmacist team to meet the challenges of the Brazilian Unified Health System (Sistema Único de Saúde, SUS).