Yes, you definitely have a U.S. tax filing obligation. A single member LLC is a disregarded entity for U.S. federal income tax purposes. Although the entity itself does not pay federal income taxes, the single owner is responsible for reporting the income and expense of the LLC on his/her income tax return and paying the requisite income tax, if applicable. If the LLC does not generate any U.S. source income, and you do not conduct business in the U.S. through a permanent establishment, then the LLC probably does not owe any U.S. federal income taxes. However, the IRS has recently implemented new regulations which require single member LLC's to file a Form 5472 to report the activity of the LLC. This form is filed alongside a proforma Form 1120. It is absolutely critical that you file these returns. The IRS can impose a $25,000 USD penalty for noncompliance. I highly recommend you consult a competent U.S. tax adviser that specializes in these filings.