Ambulatory care-sensitive conditions (ACSC) are defined as conditions that lead to a hospital admission of which the onset could have been prevented through a more easily accessible ambulatory sector or one that provides better quality care. They are used by health-care systems as a quality indicator for the ambulatory sector. The definition for ACSC varies internationally. Sets of conditions have been defined and evaluated already in various countries, e. g., USA, England, New Zealand and Canada, but not yet for Germany. Therefore this study aims to evaluate the hospital costs of ACSC in Germany using the National Health Service's set of ACSC. In order to calculate these costs a model has been set up for the time period between 2003 and 2010. It is based on G-DRG browsers issued by the German Institute for the Hospital Remuneration System as required by German law. Within these browsers all relevant DRG-ICD combinations have been extracted. The number of cases per combination was then multiplied by their corresponding cost weights and the average effective base rates. The results were then aggregated into their corresponding ICD groups and then into their respective conditions which lead to the costs per condition and the total costs. The total number of cases and total costs were then compared to another second source. These calculations resulted in 11.7 million cases, of which 10.7% were defined as ambulatory care-sensitive. Within the analysed time period the number of ambulatory care-sensitive cases increased by 6% in total and had a 0.9% CAGR. The corresponding costs amounted to a total of EUR 37.6B and to EUR 3.3B for ACSC. 60% of the costs were caused by three of the 19 ACSC. These results validate that it is worthwhile to further investigate this quality indicator for the ambulatory sector.