Through the Bank

• 1). Gather the personal information of the decedent, including his Social Security number and the address of the estate, along with proof of your identity, such as a driver's license or state-issued photo identification. You may also need to provide documentation showing your status as executor.
  
  
• 2). Visit the bank or credit union where the estate's bank account is currently located. This is the account that opened for the estate upon the decedent's death.
  
  
• 3). Provide a bank representative with the account number of the estate's account. Confirm the name of the decedent, and provide your identification and other documents to prove you are the executor handling the estate's affairs.
  
  
• 4). Ask the representative to provide you with the estate tax ID number listed for the bank account. The ID number may also be referred to as an EIN or a TIN.
  
  

Through the IRS

• 1). Gather your personal information, including your Social Security number, and the personal information of the decedent, including his full name, date of birth, date of death, and Social Security number. You will also need to provide the address of the estate, which is usually the physical address of the property the decedent owned and maintained as his primary residence.
  
  
• 2). Contact the IRS Business & Specialty Tax Line by calling (800) 829-4933. The line operates between 7:00 A.M. and 10:00 P.M., Monday through Friday. There is also an automated system that you can use when live help is unavailable to look up an estate tax ID number if you have the appropriate information available.
  
  
• 3). Provide the IRS agent with your personal information and the information of the decedent, specifically his Social Security number. Also provide the address of the estate and the estate's bank account number. You may be asked to fax a signed document confirming you are the executor, or other estate-related documents before the agent can provide you with the estate tax ID number.