The satisfaction level is partly blamed on the worst recession since the 1930s
An annual survey suggets that Americans who still have a job are less satisfied with their work than at any time in the last two decades.
Researchers found that only 45% of workers were happy with their jobs, dropping from 49% in 2008.
The Conference Board research group concluded that the recession was only partly to blame for the drop.
They said dissatisfaction had been growing because incomes were not keeping pace with inflation.
Another reason was that fewer people were finding their jobs interesting.
The job satisfaction level was the lowest recorded by the Conference Board in more than 22 years of studying the issue.
"It says something troubling about work in America. It is not about the business cycle or one grumpy generation" says Linda Barrington, CB's managing director of human capital.
The researchers added that the soaring cost of health insurance had affected workers' salaries.
Economists say that if the job satisfaction trend is not reversed, it could affect US productivity and competitiveness.