Our study aimed to enhance understanding of memory decline (MD) in old age by evaluating longitudinal effects of personal and national contributing factors. We used data collected by the Survey of Health, Ageing and Retirement in Europe (SHARE) from 12 European countries and Israel. Our sample included 11,930 retirees aged 50+, interviewed at baseline and four years later. MD was evaluated by the change in the number of recalled words from first to second interview. Except for gender, all of our explanatory variables had a significant unique effect on MD – age, education, type of occupation, European geographical region, early retirement, time elapsed from retirement, reason for retirement, active lifestyle, re-employment, health/function status, depressive symptoms, and decline in physical and mental health – over the four years of the study. Our findings indicate that MD can be postponed by national policies such as those which prolong years of education and participation in the workforce, and by social interventions directed to promote active lifestyles in late life, especially in Mediterranean and Eastern European nations.