“I’ve been working the land since I was a boy, and it’s the first time I’ve seen anything like it,” said Khalil Semhat, 56, a farmer near the city of Tyre 50 miles south of Beirut.
Describing his find as a “giant”, Mr Semhat displayed the potato for a photographer on a large set of scales.
The tuber was so heavy Mr Semhat said he had to call on a friend to help him pry it from the ground, according to AFP.
His farm, damaged during Israel’s heavy bombardment of south Lebanon during a brief war in summer 2006, mostly grows potatoes and bananas.
Despite the freakish size of the vegetable, Mr Semhat insisted he had used no artificial fertilisers: “I didn’t use any chemicals at all,” he said.
Mr Semhat hopes to have the potato registered by Guinness in its next book of records.