The highly unusual proposal to stop dogs leaving excrement on the pavement was made by fed-up Spanish officials.
The mayor of Madrid, Manuela Carmena, revealed on Wednesday the city council is working on the development of a pet DNA database to identify the excrement and fine the owners.
Residents in the district of Tetuán were told of the plan to solve the persistent lack of cleanliness in the capital.
Mrs Carmena said he had considered the proposal after listening to the persistent complaints of the residents, who are tired of the problem.
She revealed that the dog DNA registry would be a solution to the issue, given that, according to the mayor, it is at present “more difficult” to catch people who littered.
Mayor Carmena said: “This leads us to study the possibility, as it is done in other cities, of requiring that all pets get their DNA on a database to identify their droppings.
“We are studying this measure, perhaps it can be interesting.”
Dirt in the capital is one of the main concerns for the people of Madrid.
Several residents asked for a more thorough clean-up job of the dog mess.
Mayor Carmena, is also considering launching an awareness and prevention campaign in schools and among dog owners city wide.
Britain has already launched a pilot scheme to test the DNA of dog poo to catch owners who do not clear up after their pet.
In 2016, the London Borough of Dagenham tested the creation of a database for dogs alongside animal DNA specialists PooPrints.
And while registering dogs was voluntary, microchips are mandatory and came into force in April 2017.
Councillor Darren Rodwell at Barking and Dagenham Council told the BBC: “This scheme, which is in response to concerns raised by our residents, is about bringing considerate owners on board with us now, enabling us to gather evidence so we can get tough on inconsiderate owners later.”