Levels of customer service are 20% higher in restaurants with staff aged 60 or over - numbering approximately two-fifths of the chain's branches.
According to research from Lancaster University Business School, 69% of McDonald's managers said older workers empathise and connect well with managers, 47% said older workers would go the extra mile to deliver the best possible service and 44% rated highly the role of mature workers in bringing mentoring skills into the business to help develop younger staff.
Paul Sparrow, director of the Centre for Performance-led HR at Lancaster University, said: "The research clearly demonstrates the very real business value of recruiting an age diverse workforce. Mature employees are a key part of the performance recipe.
"This is good news for the workforce, given the changing demographics of our society. We are likely to see more and more people working for longer, either because they are sufficiently fit and healthy to do so, or to store up their financial security."
David Fairhurst, senior vice president, chief people officer at McDonald's UK & Northern Europe, added: "It might surprise people to learn we employ 1,000 people aged 60 or over. These employees play an important role in our business and make a huge impact on customer satisfaction.
"While the majority of our employees are under 30, it's good for our people and good for our business to have a diverse range of ages in our restaurants. I urge employers across the sector to realise the benefits of an age-diverse workforce."
McDonald's proves the benefits of an age-diverse workforce
Employees over 60 have delivered a significant boost to business at McDonald's.