Michael Ikenna Nduanya, 34, and his common-law spouse Nguyen Thi Hai Anh, 27, were convicted on Tuesday in Ho Chi Minh City by an Ho Chi Minh City People’s Court.
He was sentenced on March 22 for illegal transportation of hard drugs.
Sources said the couple were arrested in December 2009, but gave no further details.
The website of Tuoi Tre newspaper, citing the indictment, said Nduanya had asked his wife to collect about one kilogram of heroin from Cambodia. She was arrested at a Ho Chi Minh City bus depot after returning with the drugs, it said.
Nduanya is the third person to be sentenced to death in Vietnam this year, according to state-controlled media reports tallied by AFP. There were 80 death sentences and four executions last year, according to the tally. Most death sentences in the communist country are issued for drug and murder cases.
Michael Ikenna Nduanya, 34, confessed that he had visited Vietnam in 2008 and had met Nguyen Thi Hai Anh, 27, from Dak Lak Province and they had since lived together as husband and wife.
Wanting to earn money quickly, the couple joined an illegal trade ring to transport drugs from India to China via Cambodia and Vietnam. They received US$1,000 for each drug delivery.
Since early 2009 to December 2009 they were able to transport nearly 990 grams of dope until Hai Anh was caught red-handed illegally carrying drugs at the Mien Dong coach station in HCMC.