About 649kg (1,430lbs) of cocaine was found hidden inside a vessel that had run ashore.
Police said the drugs were incinerated on Tuesday, apart from two packets, which have been sent to the US Drug Enforcement Administration for testing.
The drug haul has an estimated street value of $80m (£61m).
Drugs often wash ashore on the Marshall Islands, but last week's discovery set a new record.
The boat was found by a local resident on Ailuk atoll. Locals tried to move the vessel but were unable to due to its weight.