Loss of body weight, as a result of imbalance between increased energy demand and/or reduced dietary intake, is a common problem in patients with COPD. The aim of this investigation was to examine the relationship between nutritional intake, change in body weight and the risk of exacerbation in patients with COPD. The study comprised 41 patients who were hospitalised because of an exacerbation of COPD. The follow-up period was 12 months. Weight, height and lung function were measured at baseline. At the 12-month follow-up, weight change and current weight were assessed by an interview and nutritional intake was recorded in a food diary for 7 days. An acute exacerbation was defined as having been admitted to hospital and/or making an emergency visit to hospital, due to COPD during the follow-up period. At baseline, 24% of the patients were underweight (body mass index (BMI)<20 kg/m2), 46% were of normal weight (BMI 20-25 kg/m2) and 29% were overweight (BMI>25 kg/m2). Energy intake was lower than the calculated energy demand for all groups. During the follow-up period, 24 of the 41 patients had an exacerbation. A low BMI at inclusion and weight loss during the follow-up period were independent risk factors for having an exacerbation (P=0.003 and 0.006, respectively). We conclude that, in patients who are hospitalised because of COPD, underweight and weight loss during the follow-up period are related to a higher risk of having new exacerbations.