The multiple collisions occurred in heavy fog on the Seoul-bound lane of a bridge that forms part of the main expressway linking Incheon airport with the capital.
The pile-up involving 105 vehicles appeared to have started when a limousine ran into the back of a car, an Incheon police station spokesman said.
The foggy conditions meant drivers could only see 15 meters in front of them, he said, adding that 63 people, including 18 foreigners, were injured.