Waterloo Region's paramedic services said staff misplaced a defibrillator in Cambridge during a shift Tuesday.
In a tweet, paramedics identified the equipment as a Zoll X-Series Advanced defibrillator.
They said staff noticed it was misplaced at 10 p.m. that night.
The equipment weighs 25 lbs or 12 kg.
Paramedics remind the public to not attempt to use the defibrillator if found.
They advise calling paramedic services at 519-588-2260 instead.