The 'I Kissed A Girl' singer fronted the ceremony in Liverpool last year and has become the only artist ever to be asked to host two successive shows.
"We spend a lot of time and energy carefully considering our potential EMA host," MTV's Bruce Gilmer said.
"It's no mean feat to take the central role at a music event of the scale and heritage of the EMAs, but Katy did an outstanding job in Liverpool - and we just kept coming back to her as first choice for this year.
"Katy's deep connection to the world of music, her dynamic and compelling personality and her worldwide appeal made her a natural choice."
Perry opened last year's show on a giant cherry Chapstick and went on to win the Best New Act gong.
Green Day, Leona Lewis and Tokio Hotel are the first acts confirmed to perform at this year's event, which takes place at the O2 World in the German capital.
> MTV Europe Music Awards: The Nominations