Three-quarters of the Latinos were in jobs that have "minimal educational requirements" such as builders and dishwashers, and typically earned much less than native-born workers, the study said.
But immigrants from other parts of the world, by and large, are better educated than the average American with a higher percentage having undertaken graduate studies.
"With the projected slowdown in the growth of the native workforce as the baby-boom generation reaches retirement age, immigrants are likely to hold an even greater share of jobs in the future," the report said.
"Barring substantial shifts in demographic trends, immigrants and their descendants are expected to provide the majority of the nation's population growth during the next half century."
one recent analysis based on data from the US census and federal agencies that estimated that in early 2004, about 10 million foreigners were in the country illegally and about 6.3 million of them were working.