The NHS Information Centre says 19 per cent of Year Six kids – aged 10 and 11 – are obese, and a further 14 per cent are overweight.
And experts lay the blame squarely at the door of parents.
Health professionals said poor eating habits in the home and kids loading up on junk food on their way to and from school is the cause for the relentless rise of childhood obesity.
"There is a lost generation of children who are totally uneducated when it comes to what they eat," obesity surgeon Shaw Somers told the Sun.
The responsibility must lie with parents.
Tam Fry, of the Child Growth Foundation and National Obesity Forum, said that when children reach school age healthy eating "goes out of the window".
"It's snacks on the way there and back," she said.
The NHS National Child Measurement Programme looked at more than a million children. In inner-city areas, the obesity figure rose to 25 per cent. But it's feared the situation could be even worse, with many heavier kids too embarrassed to take part in the NHS measuring programme.
Overweight children carry severe health risks when they grow up. Eight two per cent go on to be obese adults with a massive risk of developing Type 2 diabetes and heart disease.
"This is a really sad statistic. It is a shame that even more of our children are finishing primary school obese," said Tracy Parker, dietician at the British Heart Foundation.
"We've got to realise children's food and lifestyle choices today could have long-term consequences on their future health. Kids are turning their backs on fruit and veg in favour of snacks laden with fat, salt and sugar as a regular part of their daily diet."
Do you worry about this generation of overweight children?