Enterprises that are operating in the modern business environment are very complex organizational systems, whose operations are influenced by a large number of internal and external factors. Therefore, only companies that can effectively manage internal resources and adapt to external influences can achieve successfulness in the market. The company's top management faces many challenges that include monitoring the business efficiency as well as steering the company to conduct the right things, through which it can differentiate itself from its competitors and achieve a strong market position. Although all organizational units are somewhat included in business planning and control, controlling unit has the most important role, since controlling activities are mainly focused towards business planning and control. Controlling can be functionally divided into operational and strategic controlling, whereby operational controlling focuses on day-to-day business activities, while strategic controlling focuses on supporting management in understanding and directing the long-term aspect of the business. Furthermore, the contingency-theoretical model (KTM) provides an internal and external perspective on controlling in correlation with efficiency and effectiveness functions in enterprises. KTM lists three key components of the enterprise (environment, resources and management) that are continually interacting in order to affect the level of productivity of the enterprise, while the functions of operational and strategic controlling are manifested as the key support for company’s top management in understanding the level of efficiency and effectiveness, and the preparation of action plans for business directions. Finally, in order to gain an understanding of the contingency-theoretical model in practice, this paper will provide insight into the key business aspects of the telecommunication company. As the part of the enterprise analysis, the organizational structure will be considered, with an emphasis on key organizational and functional aspects of procurement (as the first step in the value chain), and with the emphasis on key aspects of controlling activities, as the essential support function for enterprise's top management.