The body's mummified state suggests that she could have been dead for close to a year, police said.
Residents on the street said they had not seen Vickers since last summer, said actress Susan Savage, a neighbor who discovered the body.
An autopsy will be conducted to determine the cause of death, but police say foul play is not suspected.
When Savage noticed that Vickers' mailbox was filled with old letters, she pushed open a barricaded gate to reach the house and found the body in a room with a space heater still on.
"She kept to herself, had friends and seemed like a very independent spirit," Savage said. "To the end, she still got cards and letters from all over the world requesting photos."
The "bright, intelligent" Vickers had become "paranoid" in recent years and thought she was being stalked, said Boyd Magers, editor and publisher of Western Clippings, a western-film publication. He often accompanied her to film festivals.
A voluptuous blond, Vickers was a Playboy playmate of the month in 1959 and "proved to have the perfect look for 1950s drive-in films, along with episodic television," film historian Alan K. Rode told The Times in an email.
The low-budget "Attack of the 50 Foot Woman" (1958) gave Vickers her first leading film role. She plays the town floozy who has an affair with a married man. But neither lover survives to the end credits, thanks to the fury of a scorned wife who turns into a 50-foot-tall hellion after a close encounter with an alien.
It is "one of the best bad movies ever made," The Times said in 1993, a "Grade-A turkey" with cheesy special effects and inept direction.
Vickers followed it with "Attack of the Giant Leeches" (1959), in which she portrayed a promiscuous wife who is done in by the creatures of the film's title.
"She was perfect for the part. She was so beautiful, and she was a lovely person," said Jan Shepard, who appeared in the film and often saw Vickers at film festivals.
While appearing on Broadway in "The Gang's All Here," Vickers saw "Giant Leeches" with her theater castmates, including Melvyn Douglas and E.G. Marshall, who thought "it was a lot of fun," Vickers said in the 2006 book "Science Fiction Stars and Horror Heroes."
"I did want to play other kinds of parts and to go on into bigger pictures," she said in the book, "but these things just eluded me."
She regularly acted on TV in westerns and other fare but for a time was better known for her 15-year relationship with actor Jim Hutton and her affair with Cary Grant, according to her All Movie biography.
She was born Yvette Vedder on Aug. 26, 1928, in Kansas City, Mo., to jazz musicians Charles and Iola Vedder.
At UCLA, Vickers discovered acting and left school to pursue it.
Her first film role was as a giggling girl in 1950's "Sunset Boulevard."
In 1957, she appeared in the James Cagney-directed "Short Cut to Hell" and turned toward B movies after it flopped.
"Her performances would have been fine in much, much bigger pictures," said Tom Weaver, a science-fiction film aficionado who became her friend. "She gave her all in rock-bottom B-movies."
Married and divorced at least twice, Vickers had no immediate survivors.
Times staff writer Andrew Blankstein contributed to this report.