Sams, a DFLer from Staples, served five terms in the Minnesota Senate and was chairman of the agriculture and environmental committee.
He was treated for a brain tumor in 2005. Doctors found another malignant tumor last summer. Despite declining health, Sams ran for re-election last fall but lost.
"Minnesota lost a true champion of the outdoors, agriculture and veterans today," Gov. Tim Pawlenty said in a prepared statement. "Senator Sams was loved by everyone around the Capitol for his caring nature, good humor and common sense."
Sams was appointed to a job at the Minnesota Department of Agriculture after losing his re-election bid last fall.
As a lawmaker, Sams worked on agriculture and rural issues and for pushing a constitutional amendment dedicating a fraction of the sales tax to the outdoors. He headed a Senate agriculture and environmental committee.
Sen. Keith Langseth, DFL-Glyndon, a longtime friend and colleague, says in some ways, Sams' death was a relief.
"It was just a very gruesome process to a very close friend. He was as close of a friend as I have in the Senate. It's terrible to see people go, and it's even worse to see them go like he went. It's very difficult for those of us who knew him very well," said Langseth.
Majority Leader Larry Pogemiller announced Sams' death Monday on the Senate floor. The Senate paused for a moment of silence.
"He was an asset to our country, our state, our community and most of all his family," said Rep. Mary Ellen Otremba, DFL-Long Prairie, who said her friendship with Sams was "like brother and sister." Sams worked on his own dairy farm when he was away from the Legislature. He also taught farm management in the Staples area.
He is survived by his wife, Mary Beth, and five children. Pogemiller says funeral arrangements are pending.
(The Associated Press contributed to this report)