||The dissertation thesis deals with the expected phenomenon of an ageing population in the Czech Republic, its impact on the pension system and tries to provide some possible solutions. The thesis begins with the forecast of the pension system in the Czech Republic based on current demographic projections. The outcome points to the impossibility to go on with the current setting of the pension system in next decades. The reason is obvious: ageing population. Thus, the thesis tries to find possibilities how to insure long-term stability of the pension system in the Czech Republic using single parametric changes or conversion to the mixed system. Simulations are based on OLG model, long-term demographic forecast and limits of fiscal policy stemming from the necessity to fulfill Maastricht criteria and The Stability and Growth Pact. Those obligations create a frontier for plausible solutions. Results suggest that it is possible to find a solution for mixed system providing more favorable conditions than purely parametric changes of PAYG. Taking into account fiscal limits, the contribution rate to the FF pillar would be similar to the rates in other CEE countries where the pension reform already started.