The BTS/NICE COPD guideline recommends a chest X-ray at initial COPD evaluation; this is a grade D recommendation based on expert opinion. We have investigated which pathologies other than COPD are detected by chest X-ray and how they alter management. Dundee smokers aged 40 or over and receiving bronchodilators are assessed for COPD by their practice nurse and offered a chest X-ray if there is no record of a chest X-ray within the previous three years. We retrospectively analysed the chest X-ray reports and case records of these patients. The chest X-ray report was structured with 7 specific questions, most importantly "Are there any features of other disease likely to be causing dyspnoea?" and "Are there any features to suggest lung cancer?" Management of patients with chest X-ray findings suggesting other disease causing dyspnoea or lung cancer was assessed by questionnaire and case record study. Five hundred forty-six consecutive chest X-ray reports were analysed. Fourteen percent of all chest X-rays detected potentially treatable dyspnoea causing disease; where management following receipt of X-ray reports was audited, 84% were thought to help. Eleven lung cancers were detected, 3 had stage 1 disease. Considerable benign and malignant pathology is detected by chest X-ray performed at initial COPD assessment. Clinical management is changed in the majority with a potentially treatable abnormality. This evidence suggests that the NICE guideline to perform chest X-ray at initial COPD evaluation should be elevated from a grade D to grade C recommendation.