Introduction: Primary ciliary dyskinesia (PCD) is a genetic disease characterized by anomalies in ciliary structure/function, responsible for chronic pulmonary and rhinosinus disease. To date, no study involving only adults has been publishedAims and objectives: to assess the clinical characteristics and respiratory function in adults with PCDMethods: Retrospective study in two French tertiary hospitals, focusing on adults (³18 yrs) with a diagnosis of PCD based on presence of bronchiectasis with typical ultrastructural defect of cilia and/or situs inversus (SI). We assessed clinical symptoms, respiratory function, extent of bronchiectasis on CT scans, sputum microbiology and molecular analysis.Results: 78 patients (18-77 yrs) were included. Median follow up was 8.1 yrs. 94.8% of patients had chronic rhinosinusitis. Median nasal NO was 18.9 nL/min (IQR 84.7) and half of ultrastructural defects were dynein arm defects. Respiratory function was significantly lower in women (median FEV1=60% pred, IQR=26 vs. 77.5%, IQR=33, p<0.05) and in patients with chronic airway P. aeruginosa (PA, n=21) infection (median FEV₁=60.5% vs. 75.5%, p<0.05). FEV1 (% pred) correlated with age (r=-0.24, p=0.03), chest CT score (r=-0.46, p<0.001) but not with age at diagnosis, SI or ultramicroscopy. FEV1 decline was -11mL/year (IQR=62.3) and was greater in women (-28.3mL/ yr, IQR=43.4, vs -3.8mL/yr in men, IQR=85.7, p=0.01) although age and PA status were similar. FEV₁ decline was not different between patients with or without chronic PA (-22 mL/yr vs -9 mL/yr, p=0.14). Moreover 3 patients had severe chronic respiratory failureConclusions: PCD in adults is more severe in women and in patients with chronic PA infection.