This Diagnosis paper constitutes the second of the IPCRG Guideline papers on the management of chronic respiratory diseases in primary care. Primary care health professionals are usually the first point of contact for patients who can present a wide range of initial symptoms which may or may not constitute their first presentation of a chronic disease such as asthma, COPD, or rhinitis. This paper is focussed upon the early identification and diagnosis of chronic respiratory diseases in primary care. It uses a symptom-based approach, and includes original questionnaires and diagnostic guides to help the primary care clinician proceed systematically through the diagnostic process.