Conventional chest X-rays and CT scans, performed at the time of the initial staging in 67 patients affected by Hodgkin's disease, were reviewed and compared. CT scans provided evidence of disease not shown by concomitant conventional chest X-rays in 10 patients (15%). The impact on patient management of the additional CT data was evident in 8 cases (11.9%), either changing the whole treatment plan (4 patients) or enlarging radiation ports (4 patients). Traditional prognostic features did not influence the outcome, and only hilar adenopathy adversely affected event-free survival, without however reaching statistical relevance (p greater than 0.05). Our data suggest that thoracic CT scan is helpful in drawing up the treatment plan, while its role in identifying new prognostic factors is still uncertain.