Irregular immigration by sea accounts for only a very small part of the phenomenon in general, although one attracting increasing attention. In Italy, the issue of irregular immigration from Libya has practically monopolized the entire debate about migration policies; at the European level, Libya has come to be considered a crucial country for overall stability in the South Mediterranean. That a security interpretation of irregular flows has progressively been framed through time is largely documented and this work considers how ‘security’ has played out in framing relations in one of the most important transit routes to Europe and how it has then contributed to the interpretation and management of crises which have occurred in last years.