More than 100,000 people are expected to attend the Canterbury A P show, which opens in Christchurch on Wednesday.
Celebrating its 150th anniversary, the event will be visited by the Prince of Wales and the Duchess of Cornwall on Friday, the Peoples' Day at the Show.
Canterbury Agricultural Pastoral Association president Richard Lemon, says they've never had so many animals entered to compete - 3000 will be judged in more than 1700 categories.
Mr Lemon says the show is about camaraderie between farmers and showing city dwellers the best of the region's agriculture.
Because of the 150th anniversary and the royal visit, this year's show includes extras, such as a Clydesdale horse parade and a steam engine exhibit.
The Canterbury show is the largest A P show in the country.