The enormous meal sells for 499 dollars (£302) at Mallie's Sports Grill and Bar in Southgate, Michigan, USA.
Restaurant owner Steve Mallie said it took eight hours to bake the bun big enough to hold the 185lb (84kg) burger.
He said: ''Being in the Guinness World Records book is the greatest accomplishment we've ever done.
''I've worked my entire life to build this restaurant and being able to have the notoriety of Guinness makes it just that bit more rewarding.''
The burger is baked for 15 hours before it is topped with cheese, lettuce and tomato and wheeled out into the restaurant on a trolley.
While perhaps not as exciting (or filling!) as a 54 or 70-inch pizza, Big Lou?s 42-inch pizza makes up for size with variety. Instead of being limited to just pounds upon pounds of cheese, at Big Lou?s you can get pounds upon pounds of more than five different toppings, with their ?Big Lou Super 42? that weighs in at around 30 pounds.