This study focuses on forced migration and interstate violence during international crises, as a major security concern with salient implications for international relations stability. The empirical data consists of 229 crises designated as Forced Migration Crises (FMC), identified within the 374 crises of the International Crisis Behavior (ICB) project. The study outlines a framework for analyzing FMC compared with Non-Forced Migration Crises (NFMC), presents an index of Forced Migration Magnitude (FMM), and probes three hypotheses. It points to transformations in forced migration since WWII, compares crises with and without forced migration, and explores patterns of FMM and violence. Results lead to rejection of hypothesis 1 on similarities between FMC and NFMC, supporting hypothesis 2 on considerable diversity between them. Findings on extended scope, strategic locale, enduring forced migration problems and increased violence support hypothesis 3, challenging the placement of forced migration merely as a social or humanitarian domestic concern. Instead, results show a salient increase in FMM, coupled with more severe interstate violence and war, dangerously destabilizing regions worldwide. These patterns require the integration of forced migration within crisis frameworks, as a new research agenda, to understand the nature of forced migration in the 21st century and its impact.