The research subject of this paper, entitled “Designing a Database Based on the Entity-Relationship Model Using the Example of a Car Service”, explores the possibility of creating a database using the entity-relationship method. The research was conducted for a car service that had not yet developed its information system. For the purpose of data collection, a semi-structured interview was conducted with the owner, which collected data on the organizational structure and way it does business, and which includes determining the business processes and data flows between processes. Based on the collected data, the database was set up using the entity-relationship model. This included creating business process diagrams, flow diagrams and data repositories, developing ER models and finally determining the final relations, i.e., the actual physical data model. This physical model was the basis for creating a database on the IBM DB2 server, and subsequently test data were entered into the database. Basic data manipulation were performed on the test data using an experimental method. Use of the unstructured data before modeling was compared to the structured data after modeling and data entry into the database. This approach determined that the unstructured data were not suitable for processing and use. Various reports can be created based on the data entered into the created database using SQL statements. The conclusion was that after the modeling process, creation of the database and entering the data into it, the data were far more suitable for use than unstructured data contained paper form as well as Excel and Word documents. The final issue presented in the paper is the commercial viability of development a proprietary software solution, given that a numerous available software solutions already exist on the market for small car repair shops.