The father-of-four died from cancer yesterday (Tuesday, September 29), say friends and family.
Mr Roberts was a friendly and familiar face in the city and drew many loyal customers for his famous spuds and traditional Lancashire parched peas from his Guild Tram next to the Harris Museum.
Preston born and bred, Mr Roberts grew up in Holme Slack and went to Corpus Christi R.C. High School before following in the footsteps of his father, Keith Snr - Preston's original 'spud man'.
Keith's food cart became a fixture in Preston and his death has led to hundreds of tributes from those who enjoyed tucking into his hot potatos and parched peas on a visit to the city.
These are just some of the hundreds of tributes paid to Mr Roberts on social media.
A spokesman for Preston BID (Business Improvement District) said: "Our thoughts are with the family and friends of Keith Roberts, Preston’s famous ‘spud’ and ‘parched pea’ man, who traded from his Guild Tram on the Flag Market.
"A very popular and familiar face in our city centre, he will be missed. RIP Keith."
Paying tribute to Keith, his good friend Stephen Geraghty said: "Keith Roberts did Preston proud, as did his family. In a hundred years time, people will be talking about the spud cart and potatos.
"He truly was a wonderful man and the nicest person that I have ever known."
Family friend, Victoria Duckett added: "He always had time for you and cared about what you were doing. I think that a lot of people will be in shock. He was Mr Preston!"
Joanne Sanderson is one of many Prestonians who fondly remembers calling at Keith's stall for her dinner at the weekend.
She said: "I used to get potato, cheese and beans every weekend when I was in town when I was a teenager.
"He was always happy. Such a lovely man. RIP Keith."
Another loyal customer, Jo Whittle, said: "Was forever at the potato stall over the years as it was a favourite of mine and my daughter whenever we went to town.
"So sad to hear this news. RIP Keith. Thoughts and prayers are with all of his family and friends."