The British Thoracic Society (BTS) guideline on the use of long-term macrolides in adults with respiratory disease has been published. It indicates where there is evidence to support the use of long-term low-dose macrolides and where there is not. It discusses the potential benefits of such therapy for patients and also describes the potential risks to individuals and wider populations. It seeks to provide a pragmatic approach for clinicians considering long-term macrolide therapy for their patients. This guideline has also acted as a learning exercise for the BTS in introducing the Grading of Recommendations Assessment, Development and Evaluation approach to guideline development, which will be used going forwards.