Age Concern Scotland's "fight the freeze" campaign has received more than £5,000 from 17 McDonald's restaurants.
Staff at the fast-food restaurants in Edinburgh, Livingston and Dunfermline selected the charity and raised the cash through collection buckets in the restaurants.
Jess Barrow, head of policy and public affairs for Age Concern Scotland, said that the controversial public relations history of McDonald's, including the "McLibel" trial of the 1990s and debates about the nutritional value of its food, had not been an issue.
"We didn't see it as a conflict of interest," she said. "This was local staff picking us as a charity and we're delighted. It wasn't a big corporate sponsorship deal, which may have been taken differently."
Kenny McLaughlin, manager of a McDonald's restaurant in Edinburgh, said it was part of a commitment to the community. Staff supported children's charities in the summer, and Age Concern was chosen for the winter.