Millennium Puzzle:
The Millennium Puzzle is owned by Yugi Mutou, it's uses are that it will give the owner another personality to be smart, daring and the ability to win in games. The person who loses will get punished. The soul of an ancient Egyptian Pharaoh, who sacrificed his life to seal dark powers, is sealed also in the Millennium Puzzle.

Millennium Ring:
The Millennium Ring is owned by Ryou Bakura, one of Yugi's main enemy's(in a period of time now a friend). The use of the Millennium Ring is to give the owner a second personality of evilness. It's power given to the owner: detecting other Millennium Items and also gaining their powers as well. It can also seal part, or entire souls within objects. Sealed inside the Millennium Ring is the soul of a Tomb-robber.

Millennium Anhk:
The Millennium Anhk is owned by Shaadii, an Egyptian warrior who punishes people who raid any Egyptian Tombs and Temples. The uses of that item can see through a person's heart to see their personality etc.

Millennium Scale:
The Millennium Puzzle is also owned by Shaadii, the use of that item is to judge people. If the owner asks a question, the person being asked has to answer the question honestly otherwise the Scale punishes the person being questioned.

Millennium Eye:
The owner of The Millennium Eye is called Pegasus J. Crawford (Maximillion Pegasus), an American who is a designer of magic and wizards card game (Duel Monsters in real life). The ability of that item is that it can see through a person's mind to see what they are thinking about. He was given this while on a trip to Egypt 7 years ago when peeking at a building guarding the "Pharaoh's Memory Slate", he only wanted to see his dead girl friend again, and got that wish when the Eye accepted him. When he lost to Yugi, Ryou Bakura took the Eye from him.

Millennium Tauk:
The owner the The Millennium Tauk is called Isis Ishtar, the eldest daughter of the Ishtar Family. The Ishtar Family has been guarding the Pharaoh's Memory since ancient Egypt after an undead Pharaoh sacrificed his life to seal Dark Powers within 7 items. The use of the Tauk item is being able to see the future. However, the powers of other Millennium Items are capable of altering this future. (In one chapter of the manga, Isis was dueling Kaiba, her prediction was that Kaiba would lose, however, the Millennium Rod prevented Kaiba from losing by showing Kaiba some flashbacks).

Millennium Rod:
The owner of The Millennium Rod is called Malik Ishtar, brother of Isis and the second child of the Ishtar Family. He claimed control of this item when he was 11, when his Father nearly killed his faithful servant and friend - Lisid. He has had a split personality since he was 10 when his back was engraved with the Pharaoh's Memory. His split personality came out when Lisid fell unconscious, he killed his Father with the Rod. The Rod is also capable of turning into a small knife. Shaadii told him that it was all the Pharaoh's fault, so he swore that he would use The Millennium Rod to kill the Pharaoh, who is roaming the lands searching for his memory.