The intervention integrates components for both GPs and patients. For GPs the intervention includes interactive workshops, audit and feedback reports and automated electronic prompts summarising recommended first line antimicrobial treatment and, for one intervention arm, a recommendation to consider delayed antimicrobial prescribing. For patients multimedia applications and information leaflets are included. A minimum of 920 patients will be recruited through 30 practices. The primary outcome is change in prescribing of first line antimicrobials in accordance with the Guidelines for Antimicrobial Prescribing in Primary Care in Ireland. The intervention will take place over 15 months. Data will be collected through a remote electronic anonymised data extraction system (iPCRN), a text messaging system and through GP and patient interviews and surveys. The intervention will be strengthened by the implementation of a social marketing framework and an economic evaluation.