PURPOSE: A low body mass index (BMI) is a poor prognostic marker of acute exacerbations and mortality in patients with COPD. However, the impact of overweight and obesity on COPD-related outcomes is uncertain. The aim of this study was to examine whether a high BMI is associated with the frequent exacerbator phenotype (≥2/year) in Taiwanese patients with COPD. PATIENTS AND METHODS: Data were obtained from the Taiwan Obstructive Lung Disease study, a retrospective, observational nationwide survey of COPD patients conducted at 12 hospitals in Taiwan. Multivariate logistic regression models were used to explore the association between BMI and other factors with the frequency of COPD exacerbations in these patients. RESULTS: Among the whole study cohort (n=1,096), 735 (67.1%) had no exacerbations and 148 (13.5%) were frequent exacerbators in the previous year. The BMI values of the patients with 0, 1, and ≥2 exacerbations were 23.6, 23.5, and 22.6 kg/m, respectively. In all, 256 (23.4%) and 196 (17.9%) patients were overweight (27 kg/m > BMI ≥24 kg/m) and obese (BMI ≥27 kg/m), respectively. Even after adjusting for multiple factors, overweight and obesity were associated with the frequency of exacerbations (odds ratio [95% confidence interval] 0.49 [0.28-0.87, =0.015] and 0.49 [0.26-0.94, =0.033], respectively). CONCLUSION: Our results suggest that overweight and obesity are associated with a lower frequency of COPD exacerbations in Taiwan.