Motorists had to endure considerable traffic jams as a result of the closure. It took nine hours for the fire brigade and the police to collect the water buffalo and remove them from the autobahn.
The A3 motorway near Leverkusen was temporarily closed in both directions, a police spokeswoman said. Only later in the morning was it possible to open up the motorway again.
It was a struggle to get the large animals off the road as some of them were walking between the stopped cars, the spokeswoman added. One of them had also become trapped in a guard rail and had to be freed.
The five buffalo are believed to have broken free from a nearby pasture in Leverkusen late on Sunday evening. They then sauntered toward the A3 autobahn.