Hundreds filled up for free at the Shell Gas Station on Tenth Line Road and Innes Road.
In total, 304 motorists managed to get the fuel during the 90 minute customer appreciation event.
Some waited for up to an hour in a line that stretched several kilometres down Innes Road.
"I'm just below empty, so free is good," one man told CFRA.
"Free gas!" said another.
About a half dozen Ottawa Police Officers were on scene directing traffic. The company is paying for that service.