The socio-economic changes occurred after 1989, face the problems of the pension systems of Bulgaria and Poland. The challenges faced by the social security systems called for a completely new reforming philosophy. A multi-pillar model of social protection has been introduced with the specifics in both countries.The article’s main goal is to follow the reforms implemented in the social security systems of Bulgaria and Poland by examining individual solutions in the field of social security policy, pointing out current challenges and trends in the two pension systems. [---]