It's that time of year again, the maddest day on the footballing calendar as teams up and down the country scramble to make that last-minute signing.
Premier League clubs have until 11pm tonight to work on their deals, but just what must they to do get their Deadline Day deals over the line, and what happens if they run out of time?
Here, Sportsmail gives you the lowdown on what clubs must do to ensure that last gasp panic buy gets over the line.
What must a club do to register a player?