Accounting information system is an important component of business because it provides the information needed at all levels of decision making. This thesis investigates the main features of the accounting information system and components and factors of organizing the accounting information system, with an emphasis on internal factors. Possible approaches to the organization of accounting information systems are analyzed by presenting and comparing two main approaches to the organization of accounting information systems - modular and integrated. Trends on the accounting software market, as well as possibilities of purchasing it, are also investigated. Accounting recording of purchasing and using software, maintenance costs and putting software out of use is shown in service company`s accounting software. The organization of the current accounting information system of the service company is also analyzed and a comparative overview of the functionalities and modules of the software implemented in the observed company in the period from 2019 to 2021 is given. Additionally, the reasons for transition to the new software are explained. Scientific and professional literature was used for writing this thesis, while internal documentation and company`s website were used for the analysis of the service company`s accounting information system. Factors that affect the observed company's accounting information system significantly are its activity, existing technology and human resources.