We are pleased to announce the fourth Rotterdam symposium on Pulmonary Infectious Diseases. Pulmonary infections are still an important cause of morbidity and mortality, despite the use of antibiotic therapy. Physicians are confronted with new pathogens, an- tibiotic resistance and new diagnostic tools. The aim of this symposium is to highlight the latest approaches in diagnosis and management of different pulmonary infections. We are honoured that prof. Dr. J. Hurst form the University College London will be presenting a state of the art lecture about Lung disease in primary antibody deficiency.