Queues were several miles back at around 8.30am until 10am on the Glasgow to Edinburgh motorway after she wandered from a neighbouring field onto the M8.
The animal managed to delay traffic from Junction 29 stretching to Junction 27 near Glasgow Airport.
Police were quickly called to the scene along with the farmer who owns the cow - both trying to remove her from the motorway.
But it took an hour and a half to catch the wandering cow before traffic was finally able to continue.
Waiting drivers went to Twitter to vent, with one user labelling the incident as an "udder pandemonium"
And another tweeted: "There's a cow on the M8 - I bet its causing udder mayhem. All the commuters will be milking it cos they'll be late until someone moooooves it."