The device was discovered at Hollybrook Crescent in Newtownabbey.
Several homes were evacuated while the device was made safe by Army Technical Officers.
It was later taken away for forensic examination.
Detective Inspector Millar said: “This viable device was left outside a house in a residential area where, had it exploded, could have killed or injured anyone in the vicinity.
“This completely reckless act not only endangered local residents but also caused disruption to families who had to be moved from their homes for a number of hours.
“Our enquiries into this incident are currently ongoing.
“I would ask anyone who may have seen a number of males acting suspiciously in the area of Hollybrook Crescent late on Saturday or in the early hours of Sunday morning, or anyone with any information to contact detectives in Antrim on 101.
“Information can also be passed anonymously through the independent charity Crimestoppers on 0800 555 111.”