The woman, a 47-year-old pharmacist identified by her surname Cho, had managed to keep her late husband's corpse in their apartment in Seoul following his death in 2007, local police said.
But the body showed little sign of decomposition when it was discovered following an anonymous tip, a Seoul police official told AFP.
"It was fairly clean and maintained well ... We don't know how it was possible," the official said.
YTN said Cho, who owns her own drug store, had used her pharmaceutical training to embalm the body.
Cho has not been arrested, but the police official said she was still under investigation on possible criminal neglect charges.