Vandals also smashed two windows. The damage was discovered at 6:30 a.m. Friday.
RCMP confirm that they are investigating a case of criminal mischief.
Cold Lake Mayor Craig Copeland says Muslims are important and valued members of the community. He has this message for the person or persons responsible for defacing the mosque.
"I just want to say that the Muslim community is at home in Cold Lake, so maybe they need to evaluate whether or not they belong in Cold Lake," he said.
Copeland thinks the vandalism is in response to the shooting in Ottawa that killed Cpl. Nathan Cirillo on Wednesday. He says that people are taking out their frustration on the wrong place.
Mahmoud Elkadri from the mosque said that the graffiti is being removed on Friday.