Decisions about the use of antibiotics for acute respiratory infections are the most frequently reported reason for consulting a family physician. Although it varies according to the specific type of acute respiratory infections, the use of antibiotics is estimated to be 63% to 67%, well above the expected prevalence of bacterial infections thus suggesting overuse of antibiotics. Consequently, there is an urgent need for helping family physicians and their patients to improve the clinical decision making process regarding the use of antibiotics for acute respiratory infections. We will evaluate the impact of DECISION +, a multifaceted intervention program that includes training in shared decision making, reminders and feedback targeting physicians, and decision support tools targeting patients on the decision to use antibiotics for acute respiratory infections. Results from this study will lay the ground for a national strategy targeting the improvement of the clinical decision making process regarding antibiotic use for acute respiratory infections in primary care. In turn, this will increase quality of care and patient safety.