JKR uttryckte specifikt för denna fråga i en intervju 2007 ;
Jag har redigerat för tydlighet och korthet:
MA: What is the process? Do you-- Is there a spell? Is there a-- What do you have to do?
JKR: I see it as a series of things you would have to do. So you would have to perform a spell. But you would also-- I don't even know if I want to say it out loud, I know that sounds funny. But I did really think it through. There are two things that I think are too horrible, actually, to go into detail about. One of them is how Pettigrew brought Voldemort back into a rudimentary body. 'Cause I told my editor what I thought happened there, and she looked as though she was gonna vomit. And then-- and the other thing is, how you make a Horcrux. And I don't even like-- I don't know. Will it be in the Encyclopedia? I don't know if I can bring myself to, ummm... I don't know.
Du måste helt enkelt göra två separata saker för att skapa en Horcrux;
- Begå ett avsiktligt och kallblodigt mord för att avsiktligt fragmentera din själ.
- Skapa en Horcrux-Spell för att ta bort själfragmentet och placera det i ett objekt