Using data from the first nine months of the year, the Venice-based Leone Moressa foundation said 2.4 million residents born outside of Italy were in jobs.
Those workers together produced 8.8 percent of Italy’s national wealth, a figure that equates to over €123 billion.
Foreign-born people in Italy also had a higher rate of employment than Italians: 57.1 percent against 41.8 percent.
Almost half work in the service sector while over 600,000 run their own business.
Despite the persistent debate over immigration in Italy, the think-tank said that "from a strictly economic point of view, you can’t underestimate the contribution that migrants generate in terms of wealth and development."
Immigrants are also less of a burden on the national health service and pension fund, the think-tank added.