Officials with the Joint Rescue Coordination Centre say the twin-engine SA-226 Metro II took off from YVR at 6:43 a.m. PT and was supposed to land at YXS at 8 a.m.
However, NavCanada's Kamloops Flight Information Centre lost radar contact with the cargo flight at around 7 a.m., when the flight was northeast of Vancouver.
Vancouver and Prince George airport authorities are working with the Joint Rescue Coordination Centre in the search for the plane.
A Canadian Forces Cormorant aircraft has been deployed to trace the route of the missing plane.
Operations at Vancouver international Airport and Prince George Airport are not affected.