The aim of this paper is to find a possible solution that would be applicable in the current economic conditions of the Slovak Republic to increase the sustainability of the first tier with a focus on replacement rate. If we would like to find the optimal solution for the pension system we should consider that replacement rate is one most crucial part. The current structure of the pension system of the Slovak Republic is not optimal and significantly caused the annual increase of public debt. On the other hand, people in retirement age are still not satisfied with their incomes. Part of the work is analysis of current approaches to the pension system in different countries. We compare main indicators such as gross pension replacement rate, replacement rates for mandatory and voluntary pension schemes. Based on this analysis we will propose our recommendations for structural changes in the Slovak pension system. Obviously, we consider long term conditions of public pension expenditure.