While many workers are confident that they'll be able to pay for basic expenses during retirement, they often have little in savings or investments, according to a survey conducted by the Employee Benefit Research Institute (EBRI).
The study found that just 16 percent of workers said they're "very confident" about their retirement income.
Meanwhile, 19 percent of retirees said they are "very confident" about having enough money to live comfortably throughout their retirement.
Overall, almost 40 percent of retirees said they are not confident about having enough money, up from 32 percent last year and 34 percent in 2008.
The study also found that fewer Americans are saving. Only 69 percent of respondents said they and/or their spouse had saved for retirement in 2010, down from 75 percent in 2009.
Finally, nearly 30 percent of all respondents said they haven't saved any money for retirement, saying they simply couldn't afford to save.