Background: The aim of this study was to describe the antibiotic prescribing rate in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD), to analyse predictors for antibiotic prescribing and to explore the influence of the use C-reactive protein (CRP) rapid test. Methods: A cross-sectional study was carried out in January and February 2008 in primary care. General practitioners (GPs) from six countries (Denmark, Sweden, Lithuania, Russia, Spain and Argentina) registered all patients with AECOPD during a 3-week period. A multilevel logistic regression model was estimated using two hierarchical levels, (i) patients and (ii) physicians, and was used to analyse the association between antibiotic prescribing and potential predictors for antibiotic use: patients' age and gender, duration and symptoms and signs of exacerbations (fever, cough, dyspnoea, sputum volume and purulence) and the results of the CRP test. Results: A total of 617 GPs registered 1233 patients with AECOPD. A total of 970 patients (79%) were prescribed antibiotics, varying from 49% (Denmark) to 93% (Russia). The presence of purulent sputum was the strongest predictor for antibiotic treatment (odds ratio [OR] 8.7; 95% confidence interval [CI] 5.9-12.8). CRP determination was carried out mainly in Denmark and Sweden and its use was the strongest protective factor for antibiotic therapy (OR 0.3; 95% CI 0.2-0.6). GPs that used CRP testing weighted purulent sputum lower than GPs who did not use CRP testing. CRP values had a strong influence on the antibiotic prescribing rate. Conclusions: Antibiotic treatment for AECOPD is very high. This study shows that GPs performing CRP rapid tests prescribe fewer antibiotics than those who do not.