Ford, a three-time former NBA coach, was hired on an interim basis.
"Chris will be the coach through the end of the season and then we'll have an evaluation process," General Manager Billy King said.
The 76ers struggled under Ayers and are in danger of missing the playoffs for the first time in six years with a 21-31 record. They've lost 11 of their last 14 games.
"It's not fair to point at one person, but it's the nature of the business," King said. "We just have not played well over a long stretch of games."
Ayers had succeeded Larry Brown who left the team after last season and became coach of the Detroit Pistons.
Ayers' firing came two days after the 76ers' star player, Allen Iverson, referring to tension on the team, said, "Things are not getting better so maybe a change is needed."
Ford, 54, a onetime NBA player, formerly coached three teams in the league -- Boston, Milwaukee and the Los Angeles Clippers.