It's actually even easier than the previous posts have indicated. As of 2012, the IRS has a "streamlined" process to help overseas non-filers rejoin the fold. Unless they have reason to think you're hiding millions offshore, the IRS will settle for returns from the last three years. The details for the policy can be found at https://www.irs.gov/individuals/interna ... procedures.

I did this a few years ago after a decade of non-filing, and it worked like a charm.

Cheers,