Will using a hard drive as a Time Machine drive erase the contents?

[hajime]

Hello, I have an external drive with some data in it. If I use it as a Time Machine backup drive, will the contents already in the drive be erased or overwritten?

 

[simsaladimbamba]

Maybe: 6. Can I use a drive with other data already on it?

 

[brand]

A more simple answer is when it asks if you want to use the drive as a Time Machine drive and you say yes then it will partition and/or drive it is asking to use.