Since the 1970s, a trend towards early exit has established itself in many European countries. That entails increasing financial strains for social security systems, approaching problems with labour force supply and the problem of unused potential of older workers due to their (often involuntary) disengagement. That study examines the institutional and organisational determinants of the early exit trend in Western Germany and Poland and future prospects thereof, mainly with the help of qualitative case studies in 31 firms at two points in time. The results confirm theories which combine rational choice and institutional approaches. Firms slowly adapt to opportunities and restrictions set by institutions (e.g. the raised retirement age). However, structural determinants clearly influence when and which adaptation patterns will be adopted. Differences between Polish and German firms with regard to the effect their personnel policy has on the integration of older workers can be explained with the country-specific national and sectoral institutions which create restrictions and opportunities for firm behaviour, and with socio-economic constraints.