||The development of Polish real estate market is connected with political changes from the end of 80-ties and the beginning of 90-ties last century. Such changes have enabled functioning market economy. Major part of real estate stock, which had previously been owned by Treasury, was transferred to state and local governmental legal persons or was privatised. According to this decision the significant group of units arrived, which nowadays owns huge real estate stock. Among the most important owners that have significant share in real estate stock in Poland can be pointed local government units, state agencies and state enterprises and universities. It should be underlined that despite of well developed organisational structures of such landowners and their real estate properties located all over the country, their activity on real estate market has mainly local scope. Among other landowners playing an important role on local markets in Poland, private enterprises (or with the share of private capital), and higher schools with supporting serving units can be mentioned. Their significance is underlined by the fact that often they are one of the basic factors of local development because of employment structure or new investments. The real estate owners, through the fact of possessing large real estate stock, have some tools and instruments to influence real estate market. Managing real estate supply usually has an impact on shaping certain values and prices on the market. The owners can also have influence on planned investment development, both by making their own investments and attracting other investors with interesting localisation and adequate real estate price. Properly conducted selling politics should be directed on the certain group of purchasers, what indirectly can lead to maintaining and shaping spatial order by developing certain spatial and ownership structure of the cities. The real estate owner, such as local government, also possesses financial instruments to manage the demand, such as taxes, duties, creating special economic zones, and technical-planning instruments – change of kind of land use, land consolidation and dividing real estate. It can be assumed, that the activities of large real estate owners can create the basis for positive changes on the area of real estate market influence. This paper is aimed on studying the direction and strength of influence of two large real estate owners on local real estate market in Olsztyn (the capital of Warmia and Mazury voivodship). The first main landowner to analyse is the commune Olsztyn and the second -University of Warmia and Mazury in Olsztyn, which is state owned university. These owners, possessing spatially significant real estate stock, have strong impact on the real estate market in Olsztyn. Commune Olsztyn owns over 7 000 flats with total area over 320 000 m2 and land over 4 000 ha, while total area of the city is about 8 000 ha. University of Warmia and Mazury in Olsztyn owns over 6 700 ha of land. What is even more, University owns didactically-research buildings, students dormitories, hotel buildings and 150 flats. University, despite of owning minor real estate stock in comparison to commune, is an important factor of local development, taking into consideration its localisation, size and owning real estate placed in strategic areas of the city, especially in the areas, where the expansion of urbanisation can be noticed. Within this article, detailed analysis of legal and economic conditions, inside of which already mentioned landowners are functioning, and their influence on real estate market would be presented. Specific purposes of researches were mainly: * The analysis of legal rules and practical procedures, as the factor disturbing functioning of the free market; * The analysis of the structure of the real estate offered to sell, let or lease; * The description of the large real estate owners impact on prices and rents on the real estate market;+ The description of the large real estate owners role in creating investment areas with described socially-spatial status. // During researches and analysis both quantity and quality methods were used. The result of the researches is the paper concerning the role and significance of large real estate owners operating on local real estate market.