It is apparent that together with the increase in the size of the enterprise, the share of more advanced IT system technologies also increases. Clear differences were observed between small and medium sized enterprises (fig. 3). Amongst medium sized enterprises a large share possessed MRP class systems, however in medium and large enterprises they were replaced by more advanced ones offering more ERP class systems. In most enterprises (apart from large ones) data deriving from simple accounting systems are used (These dependencies were also considered in subject literature).