There were four objectives in this study: (1) determine the incidence of cystic fibrosis (CF) in Ireland; (2) estimate the cost of diagnosing CF; (3) clarify the characteristics and outcomes of the nationwide diagnostic efforts and (4) identify disparities. Surveys were conducted to determine the number, methods, costs and outcomes for sweat tests in Ireland from 2001 through 2003. The results allowed us to determine that Ireland's CF incidence is the world's highest at 1:1353. The average cost for diagnosis was Euro 2663 per patient. Analyses of data in The Cystic Fibrosis Registry of Ireland revealed longer delays when diagnosis followed respiratory symptoms, rather than gastrointestinal signs, and also in girls compared to boys, particularly those presenting with respiratory symptoms. Although expenditures for diagnosing of CF in Ireland are relatively modest, the high incidence and age of diagnosis, as well as gender-related disparities, are sufficient to warrant investment in national newborn screening.