US President Joe Biden has pardoned all Americans who have been convicted at the national level of possessing small amounts of marijuana.
Officials estimate about 6,500 people with federal convictions for simple possession of marijuana will benefit.
But the federal pardons will make it easier for people to get employment, housing, and education, Biden said.
As a presidential candidate, Biden promised to decriminalise cannabis use, as well as expunging convictions.
He added that non-white people were statistically far more likely to be jailed for cannabis.
He is also directing the Department of Justice and the Department of Health to review how cannabis is classified under federal law.
Recreational marijuana is already legal in 19 states and Washington DC. Medical use is legal in 37 states and three US territories.