Does anyone have an idea as to how I can get the social security number of a deceased relative of mine? It's for my great grandfather. I sent away for military records and one of the optional fields of the form was for his social security number, but I don't have it. How can I get his SSN? I've tried looking on familysearch & rootsweb before. all his personal identification cards etc were thrown out years ago by my aunt. I have nothing on him personally but pictures. Am trying to find all personal records on him I can. Can anyone help?