Formalities had been delayed until after De Gea had played in Saturday's European Under-21 Championship final - where he helped Spain beat the Swiss 2-0.
But De Gea, 20, finally gets to sign his five-year contract today after being given the all-clear by medics at a private hospital near United's Carrington training ground.
Boss Alex Ferguson has spent a year scouring the globe for the right man to succeed Edwin van der Sar, 40, who retired last month.
= Fergie said: "We identified him quite a while back as one we should go for. He is a young keeper, very quick, has good presence and is an outstanding replacement for Edwin van der Sar."