Updated project metadata. Cystic Fibrosis is a life limiting disease due to mutations in the Cystic Fibrosis Conductance Gene Regulator (CFTR). This is associated with a multiorgan disease combining pancreatic insufficiency, chronic infected bronchopathy and production of a salty sweat. Increased survival of patients leads to observation of new complications, including proximal tubule transport dysfunctions with increased output of glucose, amino acids, phosphate, calcium, uric acid, and low Molecular Weight proteins, which ultimately triggers tubulo-interstitial injury and chronic kidney disease. (Jouret et al. 2007) Exosomes are membrane vesicles stemming from Multi-Vesicular Bodies. They reflect the biological state of the cell they stem from because they incorporate various bioactive molecules from their cell of origin, which can be transferred to target cells. They are therefore ideal biomarkers for early diagnosis, prediction of disease progression or response to treatment. Urinary exosomes have been largely investigated in kidney or urothelial diseases and exosomal proteins proved to be biomarkers reflecting renal cellular biology. We hypothetized that urinary exosomal proteins might be differentially expressed, according to the presence of the mutation in the CFTR gene and its correction. We analyzed urinary exosomes of patients with CF and healthy controls based on their protein content determined by high resolution mass spectrometry, in combination with Gene Set Enrichment Analysis. These results were compared to those obtained in exosomes collected in patients treated with CFTR modulators.