Counterfeit cigarettes and tobacco worth more than £500,000 were seized by police from shops in Dewsbury town centre.
Fake designer handbags, headphones and watches were also seized on Friday, January 10, in what West Yorkshire Trading Standards said was the largest haul they had seen in the last two years.
Officers from the Dewsbury and Mirfield neighbourhood police team (NPT) found 31 boxes containing more than 100,000 packets of counterfeit cigarettes in one shop alone.
If sold, they would have resulted in £500,000 in untaxed profit.
West Yorkshire Trading Standards said it was the largest haul they had seen in the last two years.
One person was arrested on suspicion of committing copyright and trademark offences.
Officers also issued one cannabis warning and seized a vehicle for no insurance.
Anyone with information should contact the NPT on 101 or Crimestoppers anonymously on 0800 555111.