The seizure was carried out during raids at two homes in the Plungington area yesterday afternoon (May 14).
Officers with the Preston neighbourhood task force led the raids after gathering intelligence from the community.
The force shared pictures of the plants 'bagged and tagged' and prepared for incineration at a local police station.
A spokesman for the force said: "Yet again another successful raid on two properties in the Plungington area.
"The total value of the plants recovered today (May 14) is estimated to have a street value of approximately £500,000.
"Success from the DPT yet again in there continued fight against crime."
Lancashire Police has been approached for more details, including whether anyone has been arrested.