Hundreds of cannabis plants were found and seized at the former Lile Tool Shop on North Road, Lancaster on Sunday.
A drugs warrant was executed at around 7.30pm on Sunday January 3.
More than 800 plants were seized from the disused building.
Two men, aged 22 and 36, of no fixed address, were arrested on suspicion of producing a Class B drug and bailed until March 29.
Anyone with info about it can call us on 101 quoting incident ref 1068 of January 3.
Alternatively they can contact Crimestoppers on 0800 555111.