Mounties say Const. Derek Pineo, 38, was the only person in the vehicle and died at the scene near Wilkie, 135 kilometres west of Saskatoon.
Police say that Pineo was responding to a call when the collision occurred. At the time, police said there was a mischief complaint and a call about a possible impaired driver.
Sgt. Paul Dawson said crash investigators were still examining the circumstances.
Pineo was based at the Wilkie RCMP detachment and joined the force in 2007.
Pineo's uncle, Rupert Pineo, said his nephew grew up in Fall River, N.S., was married and had three children.
"Derek was the kind of person that he wasn't really sure what he wanted do, but he did settle on being a Mountie and he passed the Mountie's test and he really liked his work," said the uncle, who was reached at his home in Shubenacadie, N.S.
Pineo has family in Saskatchewan as well as in Nova Scotia, police said.
Dawson said the death affects everyone in the RCMP.
"I think every member has been in a situation like Derek was in early this morning, responding to calls on a rural area across the country, so it does hit home with members across the country," he said.
"We're all part of the same family, so it's a definite loss for everybody."
Public Safety Minister Vic Toews extended his condolences to Pineo's family, colleagues and friends in an official statement on Friday afternoon.
"This is a very sad day for all Canadians. The death of a police officer in the line of duty reminds us of the devotion and sacrifice of those who serve each day to keep us safe," Toews said.
Rupert Pineo said his nephew was a fun-loving person who enjoyed hunting deer and fishing.
He said Derek's parents live in Fall River and were heading to Saskatchewan to deal with their son's death.
"They'll be devastated. They were a pretty close-knit family."
— By Rob Drinkwater in Edmonton; With files from CKRM