Continuity mistake: When Frost has the head pure-blood vampire on the beach, after he pulls out his first vampire tooth you see blood all over his mouth, but when it shows the closeup of him pulling out the other tooth, there is no blood.
Continuity mistake: When Blade gets his serum, Whistler holds his hand, then they see the girl run. In one shot, Whistler goes right, leaving the suffering Blade. In the next shot (close up on Blade), you can see that Whistler is still holding Blade's hand.
Continuity mistake: In the big fight scene in the end between Blade and Frost, the blood smear on Frost's face changes sides a few times.
Continuity mistake: The bloody makeup on Whistler's face and neck changes constantly throughout the scene when he gives his last words.
Continuity mistake: When Blade is leaving the shop towards the end he fills up 6 phials of EDHD, but he uses 9 phials total. 2 On the 2 people in the hall when he first gets to the building and then 7 more on Deacon at the end.
Visible crew/equipment: Near the start when the vampire that's been burnt gets taken into hospital, watch the big glass cabinet as he gets wheeled in by 2 doctors - the crew and the boom mic are reflected in the glass.
Continuity mistake: In the House of Erebus, right before Blade jumps off the ledge to fight Frost, you see that Karen is standing on the ledge above everything and Mercury is standing down below on the platform. But when Karen's shooting at her, Mercury is coming down the stairs from above.
Continuity mistake: In the shot where Blade knocks the serum down from the wall, he throws one at Frost, then throws five more at him and finally throws the last one in his head. That's seven shots of serum, but when he catches it behind his back there are only six in the pack.
Revealing mistake: When Blade uses his booby-trapped sword to knock down the serum from the wall at the end of the movie, you can tell the zoom in of the shot was sped up, as the rotating-timer-thing is spinning quicker than normal, and the screen is vibrating quickly.
Visible crew/equipment: In the shot where Blade and Karen are running across the rooftop from the police firing at them from the hospital/morgue window, you can see the arms of a man holding a paintball gun on the right side of the screen. Paintball guns were used to fire projectiles that mimic the spark and smoke effects of bullet strikes.
Continuity mistake: When Blade gets captured and stabbed in the room where the "Vampire Bible" is, he is not wearing an ear piece. In the next shot, he is.
Continuity mistake: When Blade gets back from the park after meeting with Frost and getting serum, he discovers Frost's men have been there, and sees Whistler. When Blade moves the tape, which is in a metal rotating stand, the stand rotates on its swivel, but in another shot it has only moved a little bit and hasn't rotated either. The tape would've been facing the other direction because the stand swivelled, but instead it remains in the same position.
Plot hole: in the room which contains manuscripts from the book of Erebus, Blade senses the child vampire but when he actually comes face to face with her, he offers her his hand as if she is human. This is only a mistake because she moved like a vampire and he showed earlier on the film that he was very capable of sensing whether people were vampires or human. Yet he didn't notice that she was.
Continuity mistake: During the final battle, right after Frost's arm regenerates and he says "It's too late, Blade!", Blade begins swiping his sword at Frost rapidly. You can hear the sound of Blade's sword slicing into Frost's shirt, and even see numerous pieces of fabric from the shirt flying about in the air as Blade shreds off pieces. Yet, for the rest of the scene, Frost's shirt is almost completely undamaged, save for one or two small tears. This makes no sense, as we had just seen and heard Blade slicing off numerous pieces of fabric from the shirt. The pieces seen flying through the air were actually added later using computer effects to make the scene look more dramatic, thus creating the continuity problem.
Continuity mistake: When Blade drops Karen off, she walks to her apartment and as she approaches the elevator a blonde woman walks up to its doors and stops, but in the following shot the blonde woman is now just coming into view and then stands behind the black woman instead of at the elevator doors.