Research has shown that social relationships are generally beneficial for mental health (Thoits 1995). However, few scholars have examined this association after the occurrence of a significant shock to the social system as a whole. The purpose of this article is to examine the relationship between social integration and war-related distress in Croatia immediately following the recent civil war. Does social integration decrease war-related distress? Does social integration buffer the effect of traumatic events on war-related distress? We analyze these questions using nationally representative survey data collected in Croatia in 1996. Results suggest that social integration has both positive and negative direct effects on distress. Being a member of informal organizations, such as sports clubs, and participating in social activities are beneficial for mental health. On the other hand, being a member of some formal organizations, such as church organizations and unions, is detrimental to mental health. There is little support for the idea that social integration buffers the effect of traumatic events on distress. Only one of thirty-six possible interactions is significant and supports the buffer hypothesis. Frequent participation in social activities buffers the effect of experiencing violence on war-related distress. Also, some forms of social integration appear to aggravate the effect of traumatic events on war-related distress. In sum, social integration does affect war-related distress after a system shock, but in complex and sometimes unexpected ways.