The demographics of cystic fibrosis (CF) are continuously changing, with adults representing a growing percentage of the patient population, which is expected to reach 50% by the year 2000. Pulmonary complications are primarily responsible for the high morbidity and mortality in this disease. Although the radiographic findings are quite specific, the correct diagnosis may not be suggested in the adult patient because of a lack of familiarity with its pulmonary manifestations in this age group. High-resolution CT (HRCT) has contributed to our understanding of the radiographic findings, especially at the level of the small airways. The role of imaging, including chest radiography and HRCT, is discussed. Issues that remain controversial include imaging in the acute pulmonary exacerbation, and the routine use of imaging as part of clinical scoring and in monitoring responses to new treatment modalities.