The double Olympic and world 5,000 and 10,000 metres champion will race over 26.2 miles for the first time and will also be up against Kenya's world record holder Wilson Kipsang, last year's winner Tsegaye Kebede of Ethiopia and Kenyan Emmanuel Mutai who set a course record in 2011.
Farah ran the first half of the London race in 2013 in an attempt to get up to speed with the course and competition.
"I gained a lot of valuable experience running part of the course alongside the top guys last year and can't wait to race the full distance in April," the 30-year-old told the London Marathon website.
"I had another great year on the track in 2013, but the marathon is my main focus this year. As a young boy growing up in London it has always been my ambition to run the London Marathon and to be able to make my marathon debut in my home town is very special," Farah continued.
One man who Farah will not be up against is Kenenisa Bekele who is expected to make his first marathon appearance in Paris the week before.
Ethiopia's Bekele narrowly defeated Farah in the Great North Run half marathon in September but his appearance in France rules out a sub plot in London between the two rivals.
- Athletics, Track & Field