MacFarlane said that his schedule did not permit him to return.
"Traumatised critics exhale: I'm unable to do the Oscars again. Tried to make it work schedule-wise, but I need sleep," MacFarlane tweeted.
MacFarlane's turn as emcee of the 2013 Oscars divided the community. Some found him funny and eager to experiment while many found him crass and unoriginal, citing a long gag about breasts.
MacFarlane, one of the most successful writers and showrunners in television, finds his schedule even busier because of his now-bustling film career. He is writing, directing and starring in "A Million Ways to Die in the West" and, eventually, should make a sequel to "Ted."
Oscar producers Craig Zadan and Neil Maron first brought on MacFarlane because he would appeal to a younger audience and because he loves musical theater. The producers will return in 2014 and had hoped MacFarlane would join them.
While the "Family Guy" and "American Dad!" creator will not be able to host, he has an idea of who should.
"I highly recommend the job, as Zadan and Meron are two of the most talented producers in the business," he tweeted. "My suggestion for host is Joaquin Phoenix."