Pupils from 30 primaries in Leicester have missed out on an event which can lead to county selection. Footballer Emile Heskey, the pound;9 million England and Liverpool striker, is a past winner.
David Dunmore, headteacher of St John's CoE school, blamed the cancellation on "increasing pressures that teaching staff find themselves under".
In his school's newsletter, he said: "While appreciating the value to the children of being able to participate in sporting events of this kind ... it is proving impossible to maintain."
The event was previously co-ordinated by retired teacher Sheila Marsh, who was secretar of the Leicester City Primary Schools Athletics Association, but she stood down last year.
"The organisation takes up endless hours," she said, "and the pressures on teachers are enormous. Athletics is just one of the things kids are missing out on."
Tom Bushby, an 11-year-old pupil at St John's, who represented his school last year, said: "We're all disappointed, it was a big event. But it's not the teachers' fault. They work really hard."
A sports tournament in Buckinghamshire involving 1,500 children from 32 schools around Aylesbury also faces the axe after 30 years. Organisers say work pressures mean they can no longer rally enough teachers to run a safe event, and this week's competition will be the last.