About 5.9 million U.S. adults own an eReader already, almost triple the number of eReader owners last year.
GfK MRI says ownership soared from only 2.1 million during the March to October period in 2009.
Ownership is now evenly split between men and women, where last year only 44 percent of the owner were women.
eReaders remain popular items, even though tablets have stolen some of the spotlight, said the research firm.
About 10 percent of Americans plan to give an eReader this Christmas, up 6 percentage points from last year, according to a Consumer Reports survey, GfK MRI noted.
GfK MRI derives its estimates from interviews with about 26,000 U.S. adults in their homes each year.
Source: GfK MRI