Ma Van Nhat, now 54, underwent surgery in 1998 after a car accident and only recently discovered that doctors had left an unwelcome gift behind when they closed him up.
Doctors discovered the 15-centimetre (six-inch) scissors near his colon after a recent ultrasound.
He had a three-hour operation at the weekend to remove the scissors, according to Ngo Trung Thang, deputy head of general affairs at Gang Thep Thai Nguyen hospital, 80 kilometres (50 miles) north of Hanoi.
"He is recovering well," Thang told AFP Tuesday.
Nhat had spent nearly two decades "eating, drinking and having a pretty normal life", according to Suc Khoe va Doi Song news site, the official mouthpiece of Vietnam's health ministry.
The ultrasound that discovered the scissors only came about after Nhat reported stomach pains.
Officials said they were searching for the doctors who performed surgery in Bac Kan province in 1998, but have not yet tracked down any culprits.