The city is following the lead of Australia, New Zealand, Japan and Singapore, where microchip implants are recognized as a good way of finding lost pets.
"The shot is like a routine shot, leaving no room for hurting or mistreating your dog," said Kim Yoon-gyu, a Seoul city government official.
The chip has a number that is linked to a database, which holds the dog's number, the owner's name, address and phone number.
Under the regulation, dog owners in Seoul must pay a fee of 19,000 won or 20 dollars, to have the dog enrolled and the chip implanted.
Those who breach the law will be fined 200,000 won.
In Seoul, there are about 650,000 pet dogs, and about 15,000 of them end up lost or abandoned every year.
The city sends stray dogs to its own animal shelter centre or the Korea Animal Rescue & Management Association.
If the creatures are not claimed by their owners, nor adopted by new owners, they are euthanized.
Some owners support the implant policy. "I love the idea as the best way to get back my dog, who often slips out of his way," said Mi-Hee, a 44-year old seamstress.
But others are wary of the unknown risks. "I don't feel like putting a chip into my dog's skin. Who knows what kinds of adverse effects would eventually come upon my dog," said Chull-Min, a poster on a Seoul-based internet forum.
Others are more defiant. "My mom says she will hide our dog to avoid paying the fine," one forum poster wrote.
"The system may only cause some mean dog owners to abandon their dog as they don't even want to bother doing the micro-chipping thing," wrote another.
Güncelleme Tarihi: 22 Şubat 2008, 17:38