AIMS: This retrospective, observational cohort study aimed to compare treatment outcomes and healthcare costs in the year after initiation of maintenance treatment with budesonide/formoterol or salmeterol/fluticasone in a German healthcare setting. METHODS: Data on German asthma patients initiating treatment with budesonide/formoterol or salmeterol/fluticasone between June 2001 and June 2005 were obtained from the IMS Disease Analyzer database. The primary outcome was the probability of treatment success, defined according to short-acting beta(2)-agonist prescriptions and switches or addition of controller medications, during the postindex year. A secondary definition of treatment success included hospitalisations and oral corticosteroid (OCS) prescriptions. Secondary outcomes included severe asthma exacerbations, defined as >or=1 OCS prescription, asthma-related hospitalisation and/or referral. The effect of treatment on costs was estimated using generalised linear models, adjusting for patient and physician characteristics. RESULTS: There were no significant differences between the budesonide/formoterol (n = 1456) and salmeterol/fluticasone (n = 982) groups in disease severity markers in the pre-index year. Patients on budesonide/formoterol had a 44% greater probability of treatment success [odds ratio (OR): 1.44; p = 0.0003] according to the primary definition and a 26% greater probability (OR: 1.26; p = 0.0119) according to the secondary definition, fewer severe exacerbations (-33.4%; p = 0.0123) and fewer OCS prescriptions (-31.5%; p = 0.0082) compared with salmeterol/fluticasone, after controlling for baseline characteristics. Adjusting for covariates, budesonide/formoterol had a significant inverse relationship on asthma-related costs compared with salmeterol/fluticasone (-13.4%; p < 0.001). Total cost (asthma- and non-asthma-related costs) was 12.6% lower for budesonide/formoterol (p < 0.0001). CONCLUSION: This study suggests that for patients with chronic asthma in Germany, budesonide/formoterol rather than salmeterol/fluticasone had a higher likelihood of treatment success, and that budesonide/formoterol is the less costly option. Although the cohorts appeared to be well matched at baseline, the results should be interpreted with caution given the observational nature of the study.