Matthew 27:3

Then Judas, who betrayed him, when he saw that he was condemned, repented himself, and brought back the thirty pieces of silver to the chief priests and elders.

The exact time Judas made that decision is not given; it has already been noted that the Sanhedrin made no use of Judas' testimony, and if they attempted to suborn him, which it may be assumed that they did, he certainly refused; and such a speculation, if allowed, would account for their hostility when he attempted later to return the money.

Even in "repentance," Judas did the wrong thing. If he had gone to his Saviour instead of to the priests, it is possible he might have been forgiven.