Her publisher, Random House, said McCaffrey died of a stroke Monday at her rural residence south of Dublin, her home for four decades. She christened her self-designed house Dragonhold.
"I have always used emotion as a writing tool," McCaffrey told the science fiction magazine Locus in a 2004 interview. "That goes back to me being on the stage. The thing is, emotion — if it's visibly felt by the writer — will go through all the processes it takes to publish a story and still hit the reader right in the gut. But you have to really mean it."
She was the first woman to win the top two prizes for science fiction writing, the Hugo and the Nebula, in 1968 and 1969 respectively, after publication of her first two novellas set on the fictional planet of Pern.
McCaffrey was born in Cambridge, Mass., on April 1, 1926, and graduated from Radcliffe College in 1947. She moved to Ireland in 1970 after filing for divorce from her husband of 20 years. She had ancestral ties to Ireland, which also had just launched a unique program to woo novelists to live there exempt from income tax.
Her popularity surged with the 1978 publication of "The White Dragon," which completed her original trilogy begun in the late 1960s. It was her only novel to break onto the New York Times best-seller list.
But she maintained a prolific writing pace, producing 21 more novels set in Pern at various periods of its imagined history.
Over the last decade as her health faded, she increasingly collaborated with her son Todd, who coauthored five Pern-based novels and wrote three others on his own. The 23rd novel, "Dragon's Time," was published in June with mother and son sharing the writing credit, while the 24th, "Sky Dragons," is set for publication next year.
She is survived by two sons and a daughter.