Owner and operator Tony Coulston opened his shop doors early for customers lined up outside at 6.15am.
The first shopper was given a $100 voucher, but still spent $700 on two trolley-loads of product.
"We thought, oh my gosh, what are we in for? Since then it hasn't let up," Mr Coulston said.
The Andersons Bay Rd store was the first Mad Butcher to open in Otago and Southland and the 37th franchise nationwide.
Mr Coulston said it had been a "mammoth effort" getting the store opened and he was thrilled to see it teeming with customers.
"I'm just looking forward to giving Dunedin [people] what they want. Our goal is to have the cheapest everyday low meat prices in Dunedin and I don't think that's going to be an issue," he said.
Mad Butcher founder and brand manager Sir Peter Leitch, of Auckland, was on site yesterday to welcome customers and spread excitement.
He also planned to hold a free barbecue at the premises today from 10am to 2pm.
Sir Peter said that he was extremely proud of the business and only had praise for Mr Coulston and the Dunedin store.
"It would be one of the nicest stores that has been opened. It's got a great layout and the response has been very positive," he said.
Few would be surprised to learn Sir Peter was "a big meat-eater" and his favourites included crumbed lamb cutlets and "a nice bit of steak".
He was also fond of Mad Butcher sausages, which he said were the first New Zealand-made snags to carry the Heart Foundation tick.
Sir Peter said business was booming because "people love top-quality meat at competitive prices".
All Mad Butcher mutton, beef, chicken and lamb was boned, cut and packaged on site at the Dunedin store.
The stock for beef and mutton was killed in Oamaru, and for pork in Ashburton.
"Just look at the people flocking in here. The price of meat will drop around Dunedin now," Sir Peter said.
A keen sports ambassador, Sir Peter also attended last night's match between the Highlanders and Chiefs.
The Warriors' ambassador and honorary number 19 player, Sir Peter said there was every possibility the team could play in Dunedin at the Forsyth Barr Stadium.
"There's quite a support base for the Warriors down here so we could have a match. Definitely don't rule it out," he said.
