To increase the efficiency of the business in times of the globalization and increasing competition, the management of the companies looks for opportunities to achieve higher incomes or to reduce the costs of inputs. One of possible methods to obtain higher efficiency is to put the emphasize on the relationships with suppliers. This is very important element of an effective management of the company, because by determining the economical conditions of the cooperation, it is possibly to reduce the cost of business activities. The reliable classification of the suppliers is depended on the level of the detail of an assessment criteria and the scoring method. The main problem is the risk of the objective estimation of individual offers received from the suppliers. For this reason, the classification of suppliers is one of the key problems of the logistics controlling. Based on practical example, this paper presents the complexity of the problem of the classifications and the selection of suppliers according to different hierarchy of the importance of various criteria.