The 92-year-old monarch was attending the QIPCO British Champions Day , which was basking in October sunshine.
She presented trophies for a number of races, including that to jockey Oisin Murphy after roaring Lion won the Queen Elizabeth II Stakes Race.
The Queen looked in great spirits as she made her way around the course and was all smiles as she watched the day’s proceedings.
Her attendance at Ascot came less than 24 hours after she was pictured appearing to be shopping for a new hat as she stepped out to go to Bracknell Town Centre.
The monarch looked fresh in an aquamarine coat as she braced the chilly autumn temperatures.
She wore a matching hat that was fashioned with pink roses and she carried a black bag that was held with matching black gloves.
She toured the £240 million makeover of the town centre, which has seen post-war buildings demolished and a social, shopping and cultural destination created.
The Queen toured the shopping centre and popped into the high-street shop Fenwick where a display of multi-coloured hats caught her eye.
In the department store, Angela Basten, occasion hat buyer for Fenwick, showed the Queen some of the creations on offer to customers.
She pointed out an unusual £895 hat by milliner Rachel Trevor-Morgan, who had also created the hat worn by the Queen for her visit, and another made by Vivien Sheriff from partridge and goose feathers costing £995 that looked like a snug fit.
The Queen was also all smiles on Wednesday as arrived at the Royal Air Force Club to mark its centenary year in Her Majesty’s first appearance outside Buckingham Palace.
She arrived at the Royal Air Force Club (RAFC) in London in a gorgeous blue coat and matching hat decorated with green feathers.
The monarch also donned her signature double string of pearls as she emerged from the car and shook the hand of a representative from the RAFC.
Marking the centenary the Queen was shown a new stained glass window by Jo Salter – Britain’s first female fast jet pilot, who flew with 617 Squadron.
Her Majesty also unveiled a new portrait which was commissioned to celebrate 100 years of the RAFC.
The portrait, by BP Portrait Award winner Benjamin Sullivan, shows the monarch sitting in the White Drawing Room in Windsor Castle.
The Queen’s visit to the horse racing at Ascot today comes just over a week after she attended Princess Eugenie’s wedding to Jack Brooksbank at St George’s Chapel, Windsor Castle.
This will see the monarch welcome an eighth grandchild after Prince Louis and Lena Tindall were born earlier this year.
A Kensington Palace spokesman said: “Their Royal Highnesses The Duke and Duchess of Sussex are very pleased to announce that The Duchess of Sussex is expecting a baby in the Spring of 2019.
“Their Royal Highnesses have appreciated all of the support they have received from people around the world since their wedding in May and are delighted to be able to share this happy news with the public.
“The Queen, Duke of Edinburgh, Prince of Wales, Duchess of Cornwall and the Duke Duke and Duchess of Cambridge are delighted for the couple and were able to congratulate them on Friday at the wedding in person.”