This paper investigates how European countries have responded to the issue of irregular migrant labor in recent decades. The European Union has declared that jobs in shadow economies are a major pull for undocumented migrants, and since the 1990s, a number of individual states and the EU have ramped up efforts to combat irregular migrant work. This paper charts and characterizes trends in these policy initiatives over time, and across countries, in an effort to un-derstand both how states concretely go about trying to control irregular migration, and to shed light on the political economy of labor migration. I argue that European integration and asylum crises help explain the common trend toward hardening labor market controls, as well as the growing EU emphasis on the issue. Cross-national differences remain, however, in the level of effort expended on rooting out and repressing irregular migrant work; these differences reflect varying political dynamics over shadow economies and the institutionalized power of economic interest groups.