The footprints were found at the Joggins Fossil Cliffs in Nova Scotia, a UNESCO World Heritage Site known for its abundance of fossil specimens, by a local amateur paleontologist.
"This was one of the most exciting finds I have ever made and I am very pleased that, along with my colleagues, we are able to share it with the world," said Gloria Melanson, whose father Don Reid is the Keeper of the Joggins Cliff.
"Every big fossil find is by chance; it's all about being lucky and recognizing what you're looking at," Melanson said.
"When I saw the very small tail and toes I knew we had something special. I never thought it would be the world's smallest."
The footprints belonged to a small amphibian, something like a salamander, which would have roamed Earth 315 million years ago, scientists said.
The footprints measure less than a tenth of an inch in length.
The discovery was reported in the international scientific journal Ichnos.