Az Gardener said:It depends what you mean by tax ID # What I call my tax ID # is a # assigned to me by the state so when I purchase materials to be resold I give this # to the merchant and do not pay sales tax to them but to the state later after I have resold the item and taxed my customer (at a higher rate of course) I send the $$$ to the state. The other # I have is an EIN # even though I am a sole prop I have employees therefore I need an EIN #it is my ss without the dashes. I am not a tax guy and that is who you should be asking. I was very lucky that I got a very good tax guy /CPA in the beginning he has made/saved me as much as any employee. I don't make a move without consulting him first.