A Salvation Army worker in California is being rewarded for his decision to return a bag containing $US125,000 ($A135,244.79) that fell from an armoured truck.

Joe Cornell told The Fresno Bee he found the cash on Tuesday after a Brinks truck pulled away from a red light in Fresno and left the sack behind.

“I started crying and shaking,” Cornell said.

“Everything was going through my mind – the good devil/bad devil thing. What to do?”

Thoughts of the imminent arrival of his fourth grandchild soon helped him decide.

“I thought, ‘What would I want her to think of me?’ That made up my mind right there,” he said.

“I got on my radio and called my boss. ‘Hey, I found a bag of money.’ “

Cornell, 52, works in a Salvation Army substance-abuse rehabilitation program.

His duties for the organisation include working on donated trailers.

“I went down there carrying the bag like I was Santa Claus,” Cornell said.

Brinks spokesman Ed Cunningham said he isn’t sure how the truck lost the money, and he called the incident a security issue.

The company will give Cornell a $US5000 reward and make a separate $US5000 donation to the Salvation Army.