This chapter focuses on the detention of irregular migrants as an aspect of the overall State migration management policy at that time. It concentrates on the causes that led to the acute crisis, its mitigation, the lessons learned and the post-crisis actions of the government. Due to relatively high living standards, Ukraine had always been an attractive country for migrants from other parts of the Union. Due to migration and emigration, Ukraine was even one of the busiest areas in the Soviet Union during the 1960s. Estimates of the number of irregular migrants in Ukraine, made during parliamentary discussions on the draft law "On Immigration" in 2000, offered a figure of 1.6 million persons. Movements into Ukraine occurred by land, air and sea. Although non-nationals used Ukraine primarily for transit, the country was also a destination for some irregular migrants, particularly those who arrived with knowledge of Russian.