The Birmingham scoring system for chest radiographs was assessed in 40 adult cystic fibrosis patients, with particular reference to correlation with pulmonary function values. Forty 'initial' and forty 'follow-up' chest radiographs were scored. The mean initial age of the group was 17.5 +/- 5.0 years, and the mean age at follow-up was 23.3 +/- 5.3 years. The cross-sectional radiographic score correlated significantly with the values of three commonly measured, pulmonary function parameters (r = 0.65, 0.67, 0.58, P less than 0.0001). There was a significant correlation (r = 0.64, P less than 0.0001), between the change in radiographic score, and the change in percent predicted forced vital capacity (FVC%). There was a less significant correlation (r = 0.45, P less than 0.006) between the change in radiographic score and the change in per cent predicted forced expiratory volume in one second (FEV1%). We conclude that the Birmingham radiographic scoring system is suitable for quantitative radiological evaluation in adult cystic fibrosis.