They found 400 plants, a sophisticated light, heat and irrigation system and a compressor worth €70,000 when they raided a shed on agricultural land in Donard this morning.
The factory was capable of producing €250,000 worth of cannabis every two months.
One man has been arrested and is being detained at Naas Garda Station.
The garda raid was the latest under Operation Nitrogen, which was set up to investigate all aspects of cannabis cultivation.
It is the third such operation uncovered in the last month - smaller but similar grow houses were found in Navan and Donegal earlier this month.
Gardaí say along with Asian gangs, Irish criminal organisations are now becoming involved.
