Beta blockers are known to reduce mortality from hypertension and coronary heart disease after myocardial infarction. Recent health care laws in Germany did impose a medication budget for ambulatory patients only. To evaluate the effects of this administrative instrument we studied prescribing practices of beta blockers in patients transferred from inpatient to ambulatory care. Specifically, we aimed of assessing the quality and cost effectiveness of beta blocker prescriptions. In a prospective cohort study of 142 patients discharged from a tertiary care center, the beta blocker medication was continued in 130 patients (91%). Adequate quality of the medication, defined as continuation of a beta blocker in sufficient dosage, was found in 77% of patients. Cost effective prescribing practices, defined as adequate quality at a lower cost than at discharge, were documented in 10% of the patients. However, inadequate dosage or even omitting of a beta blocker was found in 23% of patients. Overall, we found high-quality prescribing practices in more than two-thirds of our patients, but documented inadequate care in more than 20%. Our study did not document any consistent pattern between medication changes and cost-effective prescribing practices attributable to medication budgeting in Germany.