An unprecedented mortality crisis befell the former socialist countries between 1989 and 1995, representing one of the greatest demographic shocks of the period after the Second World War. While it is likely that country-level variation in the post-socialist mortality crisis in Eastern Europe can be explained by a constellation of political and socio-economic factors, no comprehensive review of the existing scholarly attempts at explaining these factors exists. We review 39 cross-national multi-variable peer reviewed studies of social determinants of mortality in post-socialist Europe in order to assess the social factors behind the post-socialist mortality crisis, determine the gaps in the existing literature and to make suggestions for future research. We propose a novel methodology to determine the relative importance of variables based on the ratio of significant to insignificant findings for each variable. The literature identifies inequality, welfare payments, religious composition, democracy, economic performance and unemployment as the leading factors that have a significant influence on mortality outcomes. Existing cross-country studies fail to establish a definitive connection between mortality and diets, drinking patterns, liberalisation, trust, health expenditure and war. We also point out that the level of analysis is not a neutral methodological choice but might influence the results themselves.