When Holmwood has the gun pointed in Van Helsing's face in Lucy's crypt, Van Helsing explains about the undead. Switch to a shot behind Van Helsing and his jaw is still moving even though he has stopped speaking.
Towards the beginning of the movie, we see Harker writing in his journal with his left hand (Keanu Reeves is left handed). Towards the end of the movie, however, we see a right hand that is supposed to be Harker's, writing.
When Jack Seward is interviewing Renfield in his cell and is subsequently attacked by him, Renfield bites him on the right side of the neck. When the orderlies run in to restrain Renfield, Seward grabs the left side of his neck as if in pain.
The glass lid on Lucy's coffin disappears midway through the scene. When the men look into the coffin, the lid is present, but when Lucy walks over to the coffin, she gets in without having to open the lid.
When Harker hands Dracula the letters he has requested, Dracula has them in his hand as he moves around behind him. The shot instantly switches to an overhead shot of the scene and the letters have disappeared.
During the prologue sequence, Dracula heads out to battle through the chapel door, which opens onto a scene of the sky (a backdrop) at sunset, his army assembled before it. After the battle, he re-enters the chapel through the same door, which now opens onto a smaller space that terminates in a stone wall.
In the prologue when Dracula returns to find Elisabeta's dead body she is seen as completely dry with her hair still permed and still wearing her crown, though the surrounding floor around her seems to be wet. The only real evidence of her traumatic jump into the river to her death is the trickle of blood from her mouth and wrist.
In the scene where we are introduced to the men courting Lucy, we see Dr. Seward sitting in the sofa, while Quincy Morris is standing besides him. Quincy is clearly holding his hat in his hands. Moments later, when Holmowood enters the room, Dr. Seward rises and reveals that he has been sitting on Quincy's hat.
After Harker's escape from the castle, the nuns send a letter to Mina. She holds the letters in her hands as she approaches the stairs to Lucy's balcony. When she's climbing the stairs she no longer has them in her hands.
When Prince Vlad catches the dropped perfume bottle the hand that catches it is holding a bottle with a bright yellow fluid (the color shows up clearly against the dark leather glove). The other bottle in the second hand in the same shot, contains a much darker, almost red liquid.
Mina's hat is tilted when she's standing in front of Dracula and the wolf. It's straight when she walks toward them a moment later. Factually, in the scene where Dracula introduces Mina to the Wolf, Mina's hat was noticeably and repeatedly repositioned from the being pulled down on her forehead to being pinned on the back of her head.
When vampire Lucy enters her vault, all of the candles spontaneously ignite. There are two five-branched candlesticks at the entrance of the vault, one of which is seen to ignite in two separate shots, taken from different angles, but edited in such a way to make it look as if those same candles have been lit and almost immediately re-lit.
When the hunters are preparing to attack Carfax Abbey, two exterior shots of Renfield shouting at his cell window can be seen. The window bars are arranged differently in these shots. Furthermore, when we see inside his cell in the following scene, the window is located in a high position and deeply set into the wall, making the action of the previous scene (Renfield clutching the bars and being pulled away by attendants) extremely implausible.
When Harker arrives at the castle and Vlad's shadow is seen to emerge from the left on the hallway wall, the puppeteer manipulating the puppet casting the shadow can be seen near the end of that effect. NOTE: This error seems to have been fixed for the Special Edition DVD, released in 2007.
When Lucy is sleeping and Arthur is guarding her, Dracula appears at the window and Arthur looks up and sees him. Just before he looks up, a female voice can be heard off-screen saying "Now" to cue him to look up. (Note: This has been corrected for the 2007 DVD release.)
Dracula says that his wife, Elisabeta, drowned in a river named Arges, this is not possible because Arges does not flow through Transylvania (situated in the Northern part of Romania) but through Tara Romaneasca (situated in the Southern part of the country).
After Jonathan's hair turns gray, throughout the rest of the film, it goes back to being dark again, with very little gray, and switches back to gray. However, this is an effect of Jonathan having been subjected to predation by vampires under Dracula's aura, so it's not a surprise if his hair color changes at the same rate of Dracula's shape and power.
The shaving scene: when Dracula creeps up behind Harker, a trick mirror is used (to give the impression of Dracula having no reflection). The trick mirror is larger, and has a thicker frame than the real mirror used in the other shots of this scene.
In shaving scene, the movements of Keanu Reeves and his double are not synchronized. When Reeves lowers his hand with the razor his double (standing back to the camera) still holds the razor near his cheek.
In the long shot at the beginning of the scene where Prince Vlad bumps into Mina outside the perfume shop, just before he first runs into her, you can see the small perfume bottle he will later "catch" visible in his right hand.
The confrontation between Dracula and the hunters, following Mina's "initiation": Quincey Morris shoots the bat-demon form of Dracula towards the end of this scene, causing a wound to his chest. Presumably due to retakes and editing, the costume already appears in a damaged and blood-stained condition earlier in the scene, prior to the actual gunshot (visible from when Van Helsing repels Dracula, following the line "You must pay for your crimes").