Officers turned up about 7,000 plants in various growth stages inside the concealed space constructed beneath a hay shed near Sorrento, B.C., north east of Kamloops.
They executed a search warrant on the rural property on Wednesday on suspicions of a sophisticated commercial grow operation.
Staff Sgt. Kevin Keane says the discovery holds telltale signs of organized crime and it's believed to be part of a larger network the Salmon Arm RCMP have been investigating.
He says the home on the property appears to have been designed to facilitate a marijuana grow-op.
A 52-year-old man arrested at the scene is facing charges of production of a controlled substance.