The objective of this paper is to assess whether the pension system in the Czech Republic is sustainable in the long run – in the light of expected demographic trends – and to point out some solutions that could contribute to ensuring dignified life in old age for potential beneficiaries of old-age pensions in the years to come. In its Strategy for modernising social protection, the European Union requires all Member States to pay close attention to this issue. The expenditure on pension insurance benefits has been rising on a long-term basis in the Czech Republic, with steady increase of the share of expenditure on old-age pensions within the expenditure structure; since 1993, the expenditure on pensions has exceeded the pension insurance premium revenue by about CZK 410 billion. It is clear that the demands for the pension system will continue to mount in the years to come as a result of the population ageing; the parametric changes implemented under the first pillar of the pension system can only ensure its sustainability on a lower level. Considering the existing settings of parameters of the basic pension insurance scheme, solutions that would contribute to its long-term sustainability on a higher level should mainly be sought within the supplementary pension savings scheme.