The virus, called Megavirus chilensis, contains over 1,000 genes, and it is 10 to 20 times wider than the average virus, beating Mimivirus, the former record holder.
“It is bigger than some bacteria,” Prof Jean-Michel Claverie, from Aix-Marseille University, Marseille, France, told BBC News.
“You don’t need an electron microscope to see it; you can see it with an ordinary light microscope,” he said.
Researchers believe that the virus infects amoebas, unicellular organisms that live in the water where Megavirus was discovered.
It has hair-like structures, or fibrils, on the exterior of its shell, or capsid. Scientists believe they attract amoebas looking for bacteria displaying similar features.