SUMMARY Thesis presents object-relational mismatch research as actual problem in the information technology systems targeted for business domain applications. Programmers are working with objects, whereas they use relational databases to make the data persistent. This leads for the need to unite the two theories – object and relational. The aim of the thesis is to overview object-relational mismatch. Advantages and disadvantages are overviewed and the solutions are given. Requirements for the state-of-the-art object-relational mapping layer will be presented. Those object-relational mapping layers are used in current business processes based system. Practical aim of the thesis is to propose object-relational mapping framework for real client-server system, based on current the most popular object-relational mapping layers in the market. In the practical part of the thesis feature based analysis of selected object-relational mapping frameworks is being performed. Those object relational mapping layers are being used for tests on real insurance industry based software system. Theoretical propositions and the results discovered are illustrated with 16 pictures and 6 tables. The thesis is based on 15 different literature sources in the Lithuanian and English languages. Two appendices are given and the end of the work.