A lawyer for Domenico Dolce and Stefano Gabbana vowed the two designers would appeal the prison sentences and the 500,000 euro fine, plus the outstanding taxes, that came with them.
"Dolce and Gabbana will not go to jail now or ever," said defense attorney Massimo Dinoia.
But the prosecutor, Laura Pedio, said she was pleased with the sentence for what she called an elaborate scheme.
"This time it was not the case like the invoice for car repair," Pedio said. "This time it's serious, complicated, sophisticated tax fraud crime."
Investigators uncovered what Pedio said was a secret offshoot company set up in Luxembourg, siphoning tax revenue away from 2004 to 2007.
Four others, including Dolce's brother Alfonso Dolce and the company tax consultant Luciano Patelli, could also face prison time for their role in the scheme.
It's unclear if the verdict will affect the business of the fashion house, founded in 1985, which is one of the most recognizable labels worldwide.