The Cosmic Treadmill first appeared in The Flash #125 in 1961 and appears in comics published by DC Comics.

The Cosmic Treadmill is a piece of exercise equipment with attitude. Barry Allen, the Silver Age Flash discovered that by vibrating his molecules at a particular speed, he could travel in time or move into alternate dimensions. Finding that his control of this ability was very imprecise, Allen constructed a treadmill that allowed him greater control of the power.

When Allen ran on the Cosmic Treadmill, the device would begin to vibrate at a particular frequency that would allow the Flash to match his molecules vibrations to it. Once he had reached the desired time or dimension, the Flash was able to maintain his internal vibrations to match that time and thereby stay there until he desired to leave when he would gradually reduce his internal vibrations and return to his own time.

The Cosmic Treadmill was used during the Crisis on Infinite Earths to transport a group of villains and heroes into the past to attempt to foil the plans of the Anti-Monitor. It was also used by Wally West, Superman, and his counterpart from Earth-2 to try and breach the dimensions after the multiverse had been made whole. The Cosmic Treadmill was seemingly destroyed, but was later repaired and placed in a museum.

The Cosmic Treadmill has not been used much by the present bearer of the mantle of the Flash Wally West. It is believed that since West has a more direct connection to the Speed Force that he has no need of the Cosmic Treadmill, instead using the Speed Force to travel in time if needed.