The woman, from Yeosu in South Korea, is said to have attacked her 50-year-old husband with a kitchen knife in a fit of rage.
She knifed the man as he slept, before severing his manhood and dropping it into the toilet bowl.
Stunned neighbours – who said they thought the couple had a good relationship – heard agonising groans in the wake of the attack.
And when they went inside to investigate, they found the man writhing on the floor in agony – saying his wife had chopped off his penis.
He is now said to be “stable” in hospital while his wife handed herself in to police.
The 54-year-old woman, named only as Mrs Kim, reportedly confessed to her crimes, saying her husband frequently ignored her and was violent towards her.
She also claimed he never gave her money to live on and spent a lot of time out and playing golf.
Police said they would probe more about the motive for the alleged attack before issuing an arrest warrant, Jeju Weekly reported.
Local sources said police suspected the husband could have been attacked for cheating on Kim, but the had no evidence to back it up.