Background: Prevalence of allergic diseases and impaired pulmonary function may be high in children born prematurely. This study aimed to assess pulmonary function and prevalence of asthma, atopic diseases and allergic sensitisation in these patients. Methods: A cross-sectional study was conducted with children aged 6-14 years who were born prematurely with birth weight <2000 g from January 2008 to May 2011. Exclusion criteria were: major malformations, or acute respiratory disorders. The International Study of Asthma and Allergies in Childhood questionnaire was applied followed by allergic skin prick test and spirometry. Results: The study included 84 children aged 9.3 +/- 2.3 years born at mean gestational age of 31.8 +/- 2.4 weeks. The prevalence of current asthma was 25%, more severe asthma was 15.5%; rhinitis was 38.1%; flexural eczema was 8.3%; and a positive skin-prick test was 69.6%. Frequencies of children with values <80% of predicted were: FVC (8.3%), FEV1 (22.6%), and FEV1/FVC ratio (16.7%). Prevalence of children with FEF25-75% <70% of the predicted value was 32.4%, positive bronchodilator response was observed in 20.5% of cases, and altered pulmonary function in 42.9%. Factors associated with altered pulmonary function were oxygen dependency at 28 days of life (OR: 4.213, p=0.021), the presence of wheezing in childhood (OR: 5.979, p=0.014) and infant's height (OR: 0.945, p=0.005). Conclusions: There was a high prevalence of severe asthma, allergic sensitisation, and altered pulmonary function among children and adolescents born prematurely. Bronchopulmonary dysplasia and a history of wheezing were risk factors for altered pulmonary function. (C) 2016 SEICAP. Published by Elsevier Espana, S.L.U. All rights reserved.