Setting up a tax identification number -- also known as an employer identification number -- for a trust is a relatively simple procedure. Not all trusts require a tax identification number. If you're setting up a revocable living trust, even if it's a joint trust with your spouse, you can use your Social Security numbers instead of applying for a new tax identification number.
Trusts Requiring Tax Identification Numbers
You'll need to set up a new tax identification number for an irrevocable trust, testamentary trust, life insurance trust and a special needs trust you set up for another's benefit, which does not revert back to you if the individual dies.
Tax Identification Number
You can set up the tax identification number online with the Internal Revenue Service by visiting IRS.gov. Monday through Friday between the hours of 7 a.m. to 10 p.m., Eastern Time. You must finish the application within 15 minutes or the site will time out and you must start again. Once completed, you receive your EIN number at the end of the session. If you do not want to send personal information regarding a trust over the Internet, you can download Form SS-4 at the site, complete it and mail it to the IRS.