A promissory note is a written document in which a borrower agrees (promises) to pay back money to a lender according to specified terms. It typically includes the amount of the loan and the terms and timing of payback.

A promissory note can be prepared in conjunction with a deed of trust (or trust deed) if the lender wants to secure the note with collateral. A deed of trust creates a voluntary lien on real estate that the borrower owns or is purchasing with the loan, and it helps to ensure that the lender will get paid back.