The Middlesbrough Running Festival was due to take place over the weekend of September 4 to 6, but will now be held in 2021.
The three-day event - featuring the Alastair Brownlee 5k, Middlesbrough Fun Run and Middlesbrough 10k - was set to see two of the region's most popular road races come together on the same weekend for the first time.
The new festival will be delivered by Run For All next September, with entrants due to be informed of the postponement today (Friday, June 19).
All entries will be transferred to next year's event, with the new date due to be confirmed in due course.
Councillor Mieka Smiles, Middlesbrough Council's Executive member for Culture & Communities, said: "Middlesbrough's running events have a deserved reputation as some of the best in the UK, and I know many people were looking forward to the new Middlesbrough Running Festival.
"The races are also fantastic opportunities for local and national charities, and over the years a huge amount has been raised for good causes.
"Sadly however we've been overtaken by events this year, and in line with Government and Public Health England guidance we simply won't be able to deliver the event as we would wish.
"The decision has therefore been taken to postpone the Festival until next year - obviously it's disappointing, but I know we'll come back stronger than ever in 2021.
"I'm grateful to our partners Run For All and Everyone Active for all their hard work, and look forward to next year when we can welcome runners from far and wide to what will be a weekend to remember."
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