This article, based overwhelmingly on primary sources produced by the Yugoslav State Security Service, provides a historical overview of their work with respect to the commemorations at Bleiburg. It summarizes the stance of the Yugoslav State Security Service towards Croat émigrés by focusing on the concrete measures and the e ntire spectrum of available methods undertaken by the Service in conjunction with the commemorations. After a general summary of the work of the Yugoslav security services with respect to émigrés, the article provides detailed examination of two events separated by two decades (1966 and 1985). The 1966 commemoration was notable not only because it was the year in which the émigrés purchased a plot of land in Bleiburg, but also because the aftermath of that year's commemoration was marred by a bomb attack. The second case is the fortieth anniversary commemoration in 1985, which was perceived by both the agents of the Yugoslav state and the émigrés themselves as being particularly important. Together the two cases provide insight into the Yugoslav State Security Service's long-term operation aimed at curtailing and suppressing Croat émigré activity. The article shows that even though the Yugoslav State Security Service was willing to use violent means in this struggle, the preferred means remained infiltration, disinformation, provocation, and constant surveillance.