The purpose of this practice-based thesis is to create a warehouse management system for Karapap, which acts as the client of this thesis. Karapap uses a gathering warehouse of almost 500 square meters. Pallet racks with more than 400 Euro pallet spaces have been built in the gathering warehouse. There are about 4000 different active products. The inventory management system is required because there is no clear organization in the client's gathering warehouse, and it takes time to search for products. With the implementation of the system, it is possible to register the products in Karapap’s current ERP-system. The system will also provide an opportunity to hire an external warehouse worker.

At first, the thesis introduces the theory of warehouse management and the warehouse management system. In the thesis, the client is interviewed, and it is found out what wishes he has regarding the system. By comparing other warehouse management systems offered by enterprise resource planning systems with the client's current resource planning system, it is determined which system is the most optimal for the client.

As a result of the thesis, a functional warehouse management system was created for Karapap. This thesis presents the different steps that should be considered when creating a warehouse management system. The most important goals of the thesis are adding warehouse locations to the product information of the products and implementing a mobile warehouse management application. At the end of the thesis, an instruction for the warehouse worker on viewing the inventory data of SAP Business One products and the use of the COBI.wms application for collecting orders has been added as an appendix.