I don't know if there is any specific deadline, but I remember they told us at my interview that it's def. in our best interest to submit it as early as possible b/c the lower interest loans are given out on a first-come first-serve basis. They also recommend we submit our parent's info and that we use the electronic data match with the IRS. That held me up for awhile and I just finally got my FAFSA submitted last week.