The team had parted company with Fisher after the team had failed to live up to expectations in their first season back in California.
A statement from Los Angeles Rams owner Stan Kroenke said the team had parted company with Fisher after the team had failed to live up to expectations in their first season back in California.
"This is the right time to make a change as our performance has not lived up to my or our fans' expectations," Kroenke said.
"Our mission is to celebrate a Super Bowl title with our fans in Los Angeles. Today is the first step to bringing us closer to that goal."
The move came after a humiliating 42-14 home defeat to the Atlanta Falcons at the Los Angeles Memorial Coliseum on Sunday.
The Falcons had romped into a 42-0 lead by the third quarter before easing off in the fourth quarter.
By that stage Los Angeles fans had rained down boos on the team while many others had already headed for the exits, a public relations disaster for a team eager to establish itself as a fan favourite in the City of Angels.
The defeat left the Rams at 4-9 for the season and came just days after reports of a rift between Fisher and general manager Les Snead, which both men denied.
Fisher had been coach of the Rams for four seasons, but had compiled a mediocre 31-45-1 record during that time, with no playoff appearances.
"Making a decision such as this - especially during the season - is one of the most difficult in sports," said Kroenke.
"I have great respect for Jeff as a coach, person, father and friend.
"He has worked tirelessly despite some challenging circumstances. He played an integral role in helping this team make history in returning the NFL to Los Angeles, and we always will be grateful for his commitment and dedication to our organization."