The POSK Foundation was set-up in 1989 to support financially primarily the activities of the centre through loans and donations. The Trustees of the Foundation are elected by the POSK Council. For the year 2010/2011 the trustees are Robert Wiśniowski, Adam Ostoja-Ostaszewski, Wojciech Tobiasiwiecz, Andrzej Zakrzewski and Marcin Zaremba.

The Foundation manages four funds:

1. The Capital Fund is an endowment fund whose purpose is to generate income for the general fund and to support POSK.

2. The Tadeusz Murdzeński Fund was established though the bequest of Tadeusz Murdzeński. The income from the fund is to be used for awarding prizes for outstanding literary, scientific and fine arts works.

3. The Zdzisław Jagodziński Fund was established through the bequest of Zdzisław Jagodzinski and its income is to be used for special needs of the Library.

4. The General Fund is the accumulation of income from the Capital Fund since its inception and which has not yet been spent by the Foundation.