"This is exactly why so many millions of Americans are frustrated. They're angry, they're disgusted, at what they see as a corrupt political system in this country," the Vermont senator told CNN's Jake Tapper on "State of the Union."
Trump has refused to release his tax returns. But the 1995 records, obtained by The New York Times, showed him posting a loss large enough that he could offset it by legally avoiding paying income taxes for an 18-year period.
The paper did not look at his federal return. It obtained one page of his New York State resident income tax return as well as the first page of New Jersey and Connecticut nonresident returns.
CNN has not independently verified the documents' authenticity.
Sanders, who lost the Democratic nomination to Hillary Clinton, on Sunday chided Trump for hypocrisy.
"You've got some middle class people working longer hours for lower wages -- they pay their taxes, they support their schools, they support their infrastructure, they support the military. But the billionaires? No, they don't have to do that, because they have their friends on Capitol Hill. They pay zero in taxes," Sanders said.
"So Trump goes around and says, 'Hey, I'm worth billions, I'm a successful businessman. But I don't pay any taxes. But you, you make $15 an hour? You pay the taxes, not me,'" he said. "That is why people are angry and want real change in this country."