Purchasing is the management of the company’s external resources in such way that the supply of all goods and services which are necessary for running, maintaining and managing the company’s primary and support activities is secured at the most favourable conditions. Purchasing activitiy in companies has a technical, commercial, logistical and marketing dimention. Mutual overlaping of the areas of purchasing, logistics and marketing is fully justified. All logistical aspects in purchasing activity should be of interest to purchasing and logistics. The same applies to purchasing and marketing. However, it is unjustified to annex purchasing to one or both of the above-mentioned disciplines.