Objective: According to recent surveys, outpatient antibiotic prescribing in Germany has been comparatively low among European countries. We assessed regional variation in outpatient antibiotic use within Germany both for overall use as well as for specific antibiotic drug classes. Methods: Prescription data for the year 2003 covering approximately 90% of the total, population were analysed using the ATC/WHO defined daily dose (DDD) methodology. Data were expressed in DDD per 1,000 persons covered by the insurance and day (DID). Findings: Outpatient antibiotic prescribing in 2003 was 13.6 DID and ranged between 9.2 and 17.9 DID in the different regions examined. Low consumption regions were eastern and southern states. High consumption areas were in the west near the French and Belgian border. This regional prescribing pattern was similar for children and adults. Penicillins were the most frequent prescribed drugs, but their use density showed a relatively large regional variation (factor 3.5), with relatively low prescription frequency in the eastern states. In almost all regions quinolones were used more often than trimethoprim- sulfamethoxazole. Conclusions: The regional variation in recent outpatient antibiotic prescribing in Germany is substantial. The relatively high antibiotic use in the western part of the country is remarkable, remains unexplained and requires further study.