Background: The objective of the study was to investigate the relation of income inequality and indicators of social capital to self-inflicted injury mortality (suicide) and violence-related mortality, and to the share of total mortality that is due to these two causes of death in 35 developed countries. Methods: An ecological study including 30 European countries, including former communist countries, and five developed countries from other parts of the world was carried out. Countries were included if there was information available about mortality and income inequality, and if they had been included in the European/World Values Surveys of 2000. The main outcome measures were self-inflicted injury and violence-related mortality and the percentage of total mortality that was due to these two causes of death. Results: There were important variations between former communist Europe and other developed countries. In other developed countries income inequality was significantly, but negatively, correlated with self-inflicted deaths, but not with violence-related deaths. In former communist countries, it was found that income inequality was correlated with violence-related deaths, but not self-inflicted deaths. Only in former communist countries did adjusting for the level of preparedness to help others reduce the associations. Conclusions: The expectation that income inequality would have a relatively strong association with the two causes of death indicating mortality due to self-infliction and violence was only partly confirmed, that is, only for former communist countries and only for violence-related mortality. The expectation that adjusting indicators of social capital would lower associations was also only partly confirmed.