Background: Prescribing of antibiotics for common infections varies widely, and there is no medical explanation. Systematic reviews have highlighted factors that may influence antibiotic prescribing and that this is a complex process. It is unclear how factors interact and how the primary care organization affects diagnostic procedures and antibiotic prescribing. Therefore, we sought to explore and understand interactions between factors influencing antibiotic prescribing for respiratory tract infections in primary care. Methods: Our mixed methods design was guided by the Triangulation Design Model according to Creswell. Quantitative and qualitative data were collected in parallel. Quantitative data were collected by prescription statistics, questionnaires to patients, and general practitioners audit registrations. Qualitative data were collected through observations and semi-structured interviews. Results: From the analysis of the data from the different sources an overall theme emerged: A common practice in the primary health care centre is crucial for low antibiotic prescribing in line with guidelines. Several factors contribute to a common practice, such as promoting management and leadership, internalized guidelines including inter-professional discussions, the general practitioners diagnostic process, nurse triage, and patient expectation. These factors were closely related and influenced each other. The results showed that knowledge must be internalized and guidelines need to be normative for the group as well as for every individual. Conclusions: Low prescribing is associated with adapted and transformed guidelines within all staff, not only general practitioners. Nurses triage and self-care advice played an important role. Encouragement from the management level stimulated inter-professional discussions about antibiotic prescribing. Informal opinion moulders talking about antibiotic prescribing was supported by the managers. Finally, continuous professional development activities were encouraged for up-to-date knowledge.