Ajax announced on Saturday that they had accepted a bid of €17.5 million (£13.8m) from United for the versatile 24-year-old.
And Netherlands international Blind is now set to link up with his former national coach, Louis van Gaal, at Old Trafford.
"Ajax has completed the transfer of Daley Blind to Manchester United. The agreement already reached between the clubs was still subject to fulfillment of certain conditions," a statement from the Dutch club read.
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