A Vietnamese man says a Good Samaritan couple “saved his life” after they found his lost diaper bag that contained more than baby’s underwear.

The man, who is studying at a southern California college, thought he had lost his life savings when he, his wife and daughter visited a Christmas display in Long Beach, Calif., and left without their bag after stopping for a photo.

The backpack contained his family’s passports and US$5,000 in cash in his wife’s wallet.

Later that night Gabriel Ruiz and Gabriela Jauregui took a picture at the same spot and found the bag.

"We turn around and there's a backpack on a seat," Jauregui told local CBS station KCAL.

The pair waited a while to see if anyone would claim it, but when no one picked it up they looked inside for ID.

"We saw the wallet, opened that up and then there was just a ton of money in there," said Ruiz.

They spent the night trying to find out who it belongs to.

"The names are in Vietnamese and everything and no address on the passports,” Jauregui said.

The bag owner went back to the site that night in search of the bag, posted signs and came back again in the morning, all to no avail.

"I thought how can I get back to my country?” said the man, who is studying at a southern California college.

“How can I pay my tuition? My rent? I already have a baby."

Meanwhile, the next morning the couple found a secret compartment in the bag with papers and contact details inside. They called the number and asked the man to describe the bag.

Satisfied, they came to the address they found to return the bag to its delighted owner.

"Oh my God, I'm still shaking,” the man, who asked not to be named, said.

“You just saved my life. Can I have a hug please?"