Four people are in custody after a warrant was executed at an address in the Llangefni area yesterday.
Three men and one woman were arrested on suspicion of being concerned in the supply of drugs.
A substantial amount of what is believed to be Class A drugs and a substantial amount of cash has been seized.
Anyone with information in relation to drug dealing and drug crime is asked to contact North Wales Police on
0845 607 1001 ( Welsh Language Line ) 0845 607 1002 ( English Language Line ) or Crimestoppers anonymously on 0800 555 111.