Her body was discovered at 9.30pm on Tuesday night after an extensive search.
She had been stabbed "numerous times".
Dr Reddy worked at Glenbrook Dental Surgery in the Blue Mountains, around 70km west of Sydney. Police officials said the man died in a vehicle crash on the New England Highway on Monday night, a day after Reddy was reported missing. Her ex-boyfriend, who is the prime suspect, is said to have died in a "deliberate" road accident later.
The gruesome discovery came just hours after police issued a public appeal to find the 32-year-old from Penrith.
Preethi Reddy was last seen waiting in line at McDonald's in George Street on Sunday
Investigators believe they know who killed Dr Reddy but are pleading for more information about her whereabouts before her death.
She phoned her family at 11am, telling them she'd head home after having a late breakfast.
Police have found the body of a missing woman found stuffed in a suitcase in the back of a vehicle in Sydney's south-west, following a public appeal. She then left the restaurant and walked south through the city towards Market Street.
Inquiries revealed Dr Reddy stayed at a hotel in the CBD with her ex-boyfriend on Sunday.
32-year-old dentist, Dr Preethi Reddy, was reported missing by her family on Sunday night after she failed to return from a convention.
The head-on collision, around 340 kilometres from where Reddy's body was found, is believed to have been deliberate, they said.
A Telugu-origin doctor, Preeti Reddy, based in Sydney in Australia, was found murdered after she went missing five days ago. "It takes a lot of effort to be a dentist and she achieved it. the family's so proud that they had a daughter like that", Anand told reporters. Quoting Detective Superintendent Gavin Dengate, local newspapers reported that the duo had met in Sydney and the police are still looking at all the movements of the two.
Surveillance video showed her leaving a McDonald's in Sydney, apparently alone, around 2:15 a.m., 7 News Australia reported. "I spoke to her last Thursday and it was "see you next week" and completely normal", she said adding "Now I am just praying she will be found", Holmes said.
Preethi severed off her romantic relationship with Narde who, it seemed, could not handle the break-up.
Family friend Navniit Anand said Reddy was "a lovely human being" and her family was "shattered".