This is the first of the IPCRG Guideline papers. The IPCRG took on the task of producing an integrated guideline for the management of chronic respiratory diseases in primary care. This included some original work aimed at developing questionnaires suitable for improving the diagnosis and recognition of respiratory diseases in the primary care setting. This paper provides the background evidence and rationale for the integrated diagnostic section of the IPCRG Guideline. It focuses on identifying the unique challenges in respiratory disease diagnosis in primary care, the use of epidemiology to build a co-ordinated diagnostic framework, and the development of tools to support guideline implementation.