Continuity mistake: Close to the end of the scene where Elektra is practicing in her room with the sandbags, she throws a sai into the sandbag with Daredevils face painted on it. The camera then switches to behind her looking down the length of the room, showing the same sandbag without a sai in it.
Continuity mistake: When Daredevil and Elektra are fighting, Elektra is wearing her charm necklace in the beginning of the fight, but after stabbing DD, she is not.
Suggested correction: In the film it is shown that her necklace drops to the ground (chain break most likely) when DD manages to grab Elektra in a choke hold. This occurs about 30 seconds before she stabs him.
Factual error: Someone already mentioned the dates on Matt's invitations are different, but if July 24th was supposedly on a Saturday, then there's no way August 13th could be on a Wednesday.
Continuity mistake: When Daredevil comes home you see stairs with a wall on the right, from Daredevil's point of view, then in the next shot he's gone down one step and there's no wall on his right, it's now on his left with his dad's gloves on it.
Revealing mistake: When Elektra stabs Daredevil, it changes to a shot from behind the glass. If you pause when the glass is intact, you can see a faint circle where the glass has been made to shatter. (01:11:46)
Continuity mistake: In the scene following the death of Elektra's dad, we see Matt hitting all of his weapons and helmets to the ground. As he is he knocking down all his 'numchucks' you notice that one in the center stays on the hook. He puts his back to the wall and begins to slide down. If you look to the left of the screen the last weapon has disappeared. (01:01:50)
Factual error: When Bullseye is shot through his hands by the sniper, he spreads his hands with the palms straight outward. This would be impossible, because since the bullet went through the back of his left hand and come out the back of his right hand, the bones of his fingers would be bent accordingly. The fingers on his left hand would be bent backwards, while those of his right would be unable to open completely.
Continuity mistake: When Elektra is standing over her dead father her good luck charm is hanging around her neck. In the next shot it is tucked away in her dress. (01:00:55)
Audio problem: In one of the films final scenes after Daredevil has just defeated The Kingpin Daredevil says "Justice is served." in a close-up shot. If you watch the shot right before that close-up though you can see, but not hear, him say justice is served. (01:28:20)
Continuity mistake: In the scene where Matt Murdock's father is killed in the alley, Matt is wearing his father's robe and hood. As Matt runs towards his father's body the robe falls off and lands behind him. Matt kneels down, without turning, to hold his father, then when the camera pulls back the robe and hood have somehow moved several yards in front of them. (00:16:05 - 00:17:00)
Continuity mistake: After Electra stabs Matt with her sai, she is bent down to him, with the front of her hair raked back over her ears. When she stands up in the very next shot, her hair changes to being straightened out.
Continuity mistake: Young Matt is in the hospital. His dad walks into the room and you see a respirator machine and an IV bottle on the window side of the bed. His dad sits down on the same side. You now see the machines on the other side of the bed behind him. Matt comes over and hugs his dad, machines still behind them on the door side of the bed. The camera backs out of the door and the machines have moved to the window side of the bed again. (00:10:05 - 00:10:40)