This paper focuses on the recent pension reform choices in the East European accession countries, which have seen many developments in this highly sensitive policy area. The paper does not discuss the desirability of alternative pension reform paths but, instead, seeks to explain how different pension reform choices came to be made in five EU accession countries. Three of the countries – Hungary, Poland and Bulgaria – represent countries which have adopted partial pension privatisation, while the other two countries – the Czech Republic and Slovenia – have reformed existing PAYG schemes without resorting to privatisation. The behaviour of individual and collective actors in the pension reform arena in each of these countries and the economic, political and institutional constraints on them are analysed in an attempt to explain why some countries have opted for radical reforms while other have not.