It follows a trial with the business last summer and also PizzaExpress’ own foray into delivery with a pilot site in Exeter.
From 1 June four restaurants in London, Guildford, Leicester and Manchester will offer the service, with a nationwide roll-out planned by July.
An estimated 206 of the chain’s 460 restaurants will be signed up to Deliveroo by the end of June, ahead of global expansion.
Both businesses told The Daily Telegraph the partnership would result in a ‘significant increase’ in sales.
PizzaExpress chief executive Richard Hodgson said: “We sell about one million pizzas through takeaway already, but it’s not that convenient for customers.
He added that while he had considered launching his own delivery service, he had concluded it was “hard enough competing with Prezzo, Zizzi and Ask without trying to compete on delivery.”
He said: “There’s been a significant increase in demand for restaurant quality food delivered to the home and we didn’t expect that explosion. It’s about convenience. Some people don’t want to walk to the fridge, take out a pizza, warm up the oven and wait 11 minutes for it to cook, they prefer the tap, tap, boom of Deliveroo.”
However, he denied that the delivery deal could jeopardise restaurant bookings or reduce the number of pizzas and dough balls Pizza Express sells in supermarkets.
“People still like escaping the house and coming to us,” he said. “And during the trial last summer we looked at what happened to sales of pizzas in local shops and saw no dropoff whatsoever.”
Deliveroo founder Will Shu added: “The Pizza Express partnership will let us go into a lot of new markets. We are already working with them in other countries.”
Pizza Express recently ran a trial with Deliveroo in Hong Kong where it has 15 restaurants.