The multi-millionaire claimed that he was unsure about where Lewis would "slot into [his] organisation" and argued that she lacked creativity.
"You spoke about the pier in Margate and it looks to me that you might be at the end of the pier in this process," said Sugar. "So Mona, with regret, you're fired!"
Lewis was brought back in the boardroom alongside project manager Debra Barr and James McQuillan after their team failed in this week's 'Rebrand Margate' task.
Team Empire's attempt to rebrand the seaside town as a gay resort was unpopular with local residents and officials, who criticised the posters, leaflets and lack of conviction in the team's campaign.
Speaking to the camera, James admitted that their presentation was "cod sh**t" and described it as a "botched job".
James and Debra both blamed Mona for their failure, arguing that she was not fully behind the campaign.
"Mona did not like going for the gay community from the very start and therefore didn't want to be behind it," said Debra.
After being fired, Mona insisted that Sir Alan Sugar had made the wrong decision in axing her from the show.
"I do believe that I'm a stronger candidate in comparison to Debra and James but I've always been a fighter so this is not the end of me," she said. "I'm not going to cry over it. I did my best and I'm really proud of what I've done."
The Apprentice continues next Wednesday at 9pm on BBC One.