Thaksin Shinawatra, who for years was a central figure in Thai politics, remains very popular in his country.
The former Prime Minister will benefit from conditional release due to his age (74) and his health problems. Since his return from exile six months ago, the billionaire has been detained in a hospital.
Driven from power after a military coup, he lived in exile abroad for 15 years to escape convictions for corruption and abuse of power.
The former leader benefited from a royal pardon which reduced his prison sentence from eight to one year.