Migration, a worldwide phenomenon, has often been seen as beneficial for both the sending and receiving countries. However, post-9/11, the phenomenon is seen as a mixed blessing. It is also being realised that it is impossible to check illegal migration unless the sending country cooperates. In South Asia, India has been at the receiving end of the problem of illegal immigration from Bangladesh. This paper argues that such illegal migration is posing a threat to internal security because the issue has not been properly securitised.