WHO must file? All US citizens and permanent residents living abroad must file a tax return if the "filing requirement" is met. WHEN must we file? For 2002 returns, generally by June 15, 2003 if residing outside the US on April 15 (pursuant toRegulation 1.6081-5(a)  Extensions are possible WHAT must we file? Generally, we file Form 1040 with applicable schedules, as well as some "foreign" forms. WHY must we file? The US taxes the world-wide income of its citizens and green card holders, regardless of where they reside or work. WHERE must we file? Generally with the: Internal Revenue Service Center  Philadelphia, PA 19255-0215 HOW must we file? When residing overseas, be aware of special rules and nuances specific to international issues.