The incident happened about 1.30am today at Batu Kikir, Jempol, in Negeri Sembilan.
Berita Harian Online reported that the woman had sneaked up on her sleeping husband, undone his trousers and severed his penis with a razor blade.
The husband, a 44-year-old businessman, managed to run to the Batu Kikir police station, despite bleeding heavily.
He was then taken to the Jempol Hospital together with his severed part for possible reattachment.
Jempol police chief Superintendent Noorzainy Mohd Noor confirmed the victim had been referred to the Kuala Lumpur Hospital and attempts to reattach his severed penis, were underway.
Police have arrested the 51 year-old woman and recovered the razor blade used in the incident.
The couple were married in May last year.