Children with recurrent or persistent pneumonia often have underlying chronic cardiopulmonary disease, but few reports on this subject have been published. Children with isolated common cardiac diseases, uncomplicated bronchial asthma or with incomplete records were excluded. Of 4361 children followed during a five-year period, 107 were included in our study. Underlying causes were identified in 99.0%: immunodeficiency disorders (20.2%), cardiothoracic malformations (18.3%), syndromic conditions (14.4%), infections (10.6%) bronchiectasis (10.6%), gastro-oesophageal reflux disease (6.6%), interstitial lung disease (3.8%) and other miscellaneous conditions (15.4%). Thus, children with recurrent or persistent pneumonia should be carefully evaluated for an underlying aetiology, as early diagnosis and appropriate management will decrease morbidity and mortality in most of these children.