Pulmonary aspergillomas usually occur when Aspergillus fungi colonise lung tissue previously damaged by disease. Pulmonary aspergillomas in three adult patients with cystic fibrosis are reported--an association not previously described. At the time of diagnosis all three patients had previous long term colonisation with Aspergillus fumigatus and severe advanced destructive lung disease with lung function less than 25% of the predicted normal values. It is likely that, with increasing survival in cystic fibrosis, more adult patients will develop aspergillomas during the protracted phase of end stage lung disease that characterises the terminal years of this condition.