Cystic fibrosis (CF) is the most common severe recessive genetic disease in Caucasians. During the last years, new therapies and aggressive management of the lung disease have contributed significantly to the increased life expectancy in CF patients. A review and update of CF diagnosis and management of lung disease are included. The sweat chloride test (SCT) remains the gold standard for CF diagnosis and should be performed properly. However, in a few patients SCT results may not be conclusive to clarify the CF diagnosis. Patients with CF should be followed up in specialist Units by an expert multidisciplinary expert applying standard clinical protocols and using lung function tests, and microbiological and imaging studies. An overview with the recommendations for treatment of early onset and chronic infections due to Pseudomonas aeruginosa, Staphylococcus aureus and other uncommon pathogens is included. Furthermore, the management of other aspects of CF lung disease and complications is provided, as well as the indications for lung transplantation. This document has been prepared by the members of the CF working group of the Spanish Paediatrics Pulmonary Society to provide an update to the earlier documents published in this Journal in 1999.