Sarah Lamont from Antrim, Ireland said she hasn't doubted for a second her decision to donate both a kidney and part of her liver to save her 4-year-old son Joe.
Born with a rare condition - autosomal recessive polycystic kidney disease - Joe was forced to have his kidneys removed and has depended on constant dialysis ever since.
He has also developed advanced liver disease, which could prove life threatening without a transplant.
Joe has been on the transplant list for more than a year and his mother said she could wait no longer to get him the help he needs.
Sarah said she wants nothing more than to take Joe to Disneyland and to attend mainstream school, but is worried that delays caused by his illness will make it too hard for him to catch up with other children his own age.
"I'll be all right, I'm a very optimistic person. If I could do it today I would, the sooner the better," said Sarah.
"I would never have doubts. Joe's been through so much, there's been a few times where I've been told he's not going to make it and he always does."
Sarah said Joe's experience showed how vital organ donation was.
"I'm lucky I can give Joe a liver and kidney, but if he had a heart problem he could die waiting," she explained. "You also don't know how long organ transplants last, so he'll probably need multiple transplants in his life."
Urging others to register as a donor immediately she said: "If you're on your deathbed of course you would take an organ, so if you're prepared to take it you should of course be prepared to give."
The liver transplant is planned for January 25, with the kidney operation in the following months when both mother and son have recovered.
