Officers from the National Police have found more than 11,000 marijuana plants in green houses, vegetable gardens and orchards in the Molina de Segura area of Murcia.
In total, the find has resulted in around 3 tons of narcotics being prevented from entering the sales network.
Three people have been arrested in connection with the find and have been charged with crimes against public health.
The discovery was made as part of a campaign of intensified patrols in order to reduce the loss to the agricultural sector through an increase in thefts.
Meanwhile, other officers from the National Police have arrested two people in Madrid after a large quantity of cocaine was found hidden in imported boxes of papayas from the Dominican Republic.
The officers also found 600 euro in cash hidden in the shipment.