One in 10 workers in the UK was born abroad, according to research by the Institute of Fiscal Studies.
More than a third of working-age immigrants arrived in the UK during the past decade, according to its Immigrants in the British Labour Market report.
The research looked at data from 1979 to 2004 and analysed the type of work immigrants were doing and how easy it was for them to find employment. More than 40% of migrant workers were found to live in London.
Most ethnic workers also had poorer salaries than their white colleagues, with Bangledeshi men earning an average of 40% less. Immigrants were also more likely to be unemployed, with black Africans, Bangladeshis, Pakistanis and Caribbean migrants being the most disadvantaged groups.
More than 40% of male immigrants were found to work in the catering, motor and retail sector, compared with just 17% of the UK-born white population.
The UK's population is predicted to rise by 7.2 million in the next 25 years, and more than half of the increase will be down to immigration, the study said.