10-year-old Kaychanel Willson - whose complicated health issues mean she has to have four-hour dialysis sessions four times a week - was shown as part of a film for Great Ormond Street Hospital on Sunday night's show.
But Katie - who famously argued on 'This Morning' that children's names were linked to class - was not emotionally affected by Kaychanel's story, instead taking the opportunity to mock her name.
She tweeted: "Kaychanel has enough on her plate without me adding to it,’ she tweeted. ‘Could have been worse. KayEsteeLauder. #xfactor."
Outraged Twitter users soon hit back at the former 'Apprentice' candidate, blasting her ill-judged joke.
"Katie Hopkins is disgusting. Making fun of that sick child shown on The X Factor," one tweeted.
Another wrote: "@KTHopkins you really are disgusting. I hope your children aren’t bullied at school due to your lack of compassion and decency."
Last week, Katie was forced to apologise after cracking a joke on Twitter about life expectancy in Scotland following the fatal helicopter crash on the banks of the Clyde in Glasgow.
She was later 'axed' from 'This Morning' after a petition to ban her from TV gathered 87,000 signatures.
Katie is one of the names rumoured to be entering the 'Celebrity Big Brother' house next month.