Following the enactment of a law by President Julius Maada Bio prohibiting the death penalty which was accepted by lawmakers in July, Sierra Leone officially abolished the death penalty.
“As a nation, we have today exorcised horrors of a cruel past,” the president said in a statement quoted by AFP news agency.
“We today affirm our belief in the sanctity of life”, he added.
Rights group Amnesty International said that last year 39 death sentences were handed down.
But no-one has been executed in Sierra Leone since 1998.
Sierra Leone has now will become the 23rd African country to have abolished the death penalty, the New York Times reports.