To compare grading of chronic obstructive pulmonary disease (COPD) using Australian guidelines Confirm diagnosis, Optimize function, Prevent deterioration, Develop a self-management plan and manage eXacerbations (COPD-X) versus Global initiative for Obstructive Lung Disease (GOLD) guidelines and to assess whether this is associated with differences in other health domains affected by COPD. Adult outpatients (n = 61) with COPD were studied using lung function measurements, six-minute walk test and body composition assessments. Subjects also completed self-rated dyspnoea scores and health-related quality-of-life scales. For each patient, COPD severity was graded using both COPD-X and GOLD guidelines, and results were collectively analysed. If significant discrepancies were observed, comparisons of other health domains were carried out. After grading severity using COPD-X and GOLD guidelines, significant discrepancies were noted. Of nine subjects with no disease (normal) based on COPD-X, seven were judged to be 'mild' according to GOLD. Similarly, 11 of 12 patients with mild disease (COPD-X) had 'moderate' disease judged by GOLD, and 9 of 23 with moderate severity (COPD-X) had 'severe' COPD using GOLD. Finally, 6 of 17 patients with COPD-X-rated severe disease had 'very severe' disease using the GOLD criteria. Among patients with COPD-X severe disease, those with GOLD discordant (very severe) severity had a poorer quality of life compared with those with GOLD concordant (severe) severity (P = 0.006). Similarly, there was also a trend towards lower six-minute walk test distance and greater subjective dyspnoea in GOLD very severe patients compared with GOLD severe patients. Significant discrepancies in grading of severity exist between Australian and international COPD guidelines. Current Australian guidelines for severity grading may not fully reflect the effect COPD has on other key domains of health.