How do to I find out if my deceased father had a 401K. I don't have his place of work but I do have his ss#.

Have you been appointed his personal representative? Go to the IRS home page and find the form for ordereing an extract of his latest tax return. Fill out and file the form. The tax return should show where he worked.

Contact his place of work for the information you need.

You go though all of his personal papers, you watch their mail for the next months, you review their checking accounts.