The Hell's Kitchen star failed to show up at a dinner in June (10) for nine-year-old New Zealander Matisse Reid, who is waiting for stomach, pancreas and small and large bowel transplants and struggles to eat.
He was forced to cancel after his mum, Helen Cosgrove, suffered a minor heart attack.
Ramsay has also pulled out of a second fundraising event in Auckland, New Zealand on Wednesday (27Oct10) and another in Wellington on Thursday (28Oct10).
Organisers at Duco Events plan to sue for lost earnings and damage to the firm's reputation after selling 2,000 tickets in the hope of raising $76,000 (£51,000) to help pay for Reid's medical bills.
A spokesperson for Ramsay says, "Unfortunately, due to urgent business matters beyond Gordon's control, he was no longer able to attend the two events organised by Duco Events. We are in communication with the organisers but of course are extremely sorry for any disappointment caused.
"Until a few days ago, we were unaware that this was a fund-raising event. Gordon has every sympathy for Matisse and will be making a personal donation to Chance to Eat."
The chef has also been hit with a slew of lawsuits this year (10) relating to alleged unpaid bills.