This study is devoted to institutes operating within the Łukasiewicz Research Network. It is worth noting in this context that the wide range of activities granted by the legislator to the institutes of the Network also allows them to conduct business activities on market terms. The author of this study has therefore adopted the thesis that an institute of the Łukasiewicz Research Network will be a small or medium-sized enterprise provided that it employs fewer than 250 employees and the annual turnover does not exceed EUR 50 million, or the annual balance sheet total does not exceed EUR 43 million. This article is motivated by substantive considerations, because the title issue is of key importance both for all institutes operating within the Łukasiewicz Research Network, enterprises cooperating with the institutes, and those entities representing the State Treasury that support the development of small and medium-sized enterprises.