Objectives : This study aimed to examine the association between public social expenditure(PSE) and suicides in the 27 countries of the Organization for Economic Cooperation and Development(OECD) from 1980 to 2003. Methods : The age-standardized suicide rates and their annual change(%) were obtained from the OECD Health Data 2007. As a measure of social protection, the PSE(% GDP) was used. The covariates included the annual divorce rate(/100,000 population), fertility rate(number of children/woman aged 15 to 49 years), GDP per capita(US$ PPP), male unemployment rate(%), life expectancy(years) and alcohol consumption(liter/capita) for each country, which were all obtained from the OECD Health Data 2007 and the OECD Social Indicators 2006. Using hierarchical linear models that included these covariates, the effects of PSE on suicides(Model 1) and the annual percent change (Model 2) were examined(Model 3). Also, sub-sample analyses were done for six countries that experienced political/economic transition. Results : We could not find significant effects of PSE on suicides(Model 1), but we observed significantly negative effects on the annual percent change for men and women(Model 2). Such findings were replicated in the sub-sample analysis, and moreover, the effect size was much larger(Model 3). Conclusions : Our finding suggests that social welfare protection can be a pivotal factor for suicide epidemiology, and especially in countries experiencing a social crisis or transition.