Mr Fields will be replaced by James Hackett, who currently heads the Ford unit that works on autonomous vehicles, The New York Times reports.
The announcement is expected later today.
Ford Chairman Bill Ford and the company's board of directors are said to be unhappy with Mr Fields' stewardship of the company, whose share price has plunged almost 40 percent since he became CEO three years ago.
Ford will attempt to make up for lost US sales by cutting costs and last week announced that 1400 jobs in North America and Asia would be axed.
It hasn't been all bad on Mr Fields' watch. Last year Ford reported a record $10.4 billion in pretax earnings. However, a lower profit forecast for this year amid huge investments in "emerging opportunities", was not well-received by investors.
Mr Fields earned $22.1 million last year.