The goal of this paper was to analyse in theory, as well as in practice on the basis of a single example, the analysis of an existing MIS system of a company with more than one hundred employees. A management information system is an information system focused on providing periodical information used by managers to help them in the process of business decision making. Management information systems also procure reports and allow managers direct access to data relevant for current and past dealings of the company to be used for pursuing the most efficient and profitable functioning of the company. As already stated, this paper also examines the practical part of this subject, and the company used as an example for the needs of this paper is „Končar - Elektroindustrija“ d.d. On the basis of the aforementioned analysed company, this paper provides an insight into the historical development of the company, its structural organisation, and functions of doing business with an emphasis on the process of adoption of an MIS, its developmental fazes, as well as an overview of the current functioning of the company, its internal cohesion and the functioning of the system within it. The way companies conduct their business has changed in the past 30 years. On one hand there has been an extensive expansion of using the internet, and on the other privatisation and globalisation of companies have forced them to use different information systems in order to more efficiently and effectively react to tasks, as well as the needs of potential customers. The analysis provided in this paper clearly points to the fact that the use of information systems in a company represents efficient management of resources within it and that every company, if it strives to be more efficient, should incorporate an appropriate information system in order to function better and be adaptable to every possible situation.