The first season of the programme, created by Glee's Ryan Murphy, starred Connie Britton, Taissa Farmiga and Dylan McDermott as a family who move into a haunted house in California. The series debuted to stellar ratings and high critical acclaim, nabbing Jessica Lange, who also starred, a Golden Globe.
According to The Hollywood Reporter, part of the reason for the move to the 'Miniseries' category is that, as the actors and story of the show will change from season to season, it is actually an anthology series.
Ryan Murphy recently revealed that the second season of American Horror Story will take place in an asylum.
Stars including singer Adam Levine and Zachary Quinto, who appeared in a minor role in the first season, have signed up for the second season. Jessica Lange is returning as the lead character.
This new move will also ensure that the show will not have to go up against contenders like Game of Thrones, Mad Men, and Breaking Bad.
This is not the first instance of a popular show changing its category at the Emmys. Last month, creators of the PBS drama Downton Abbey announced that the series would be leaving the 'Miniseries' category and entering the 'Drama' category.
American Horror Story returns later this year on FX.
Watch a trailer from the first season of American Horror Story below: