Background Pseudomonas aeruginosa (PA) infection is associated with an increased morbidity and adverse prognosis in children with Cystic Fibrosis(CF). The aim of the study was to evaluate the prevalence and characteristics of PA over a ten year period at a single paediatric tertiary referral centre in Ireland. Methods This was a retrospective cross-sectional study. Patient’s case notes, microbiology laboratory results and CF Registry of Ireland(CFRI) data were used to collect the data. Results The overall chronic PA infection prevalence was 28.1%(45/160) in 2004 and 21.3%(35/164) in 2014. In 2004, 54/160(33.8%) patients were never infected with PA, 27/160(16.9%) were free for 12 months and 34/160(21.3%) were intermittently infected. In 2014; 80/164(49%) patients, 38/164(23.2%) and 11/164(6.7%) were never infected, free for 12 months and intermittently infected respectively. Conclusion There has been a decline in the overall prevalence of PA infection and a change in the pattern of prevalence over the last decade at our Centre.