Two cats were taken from the RSPCA public boarding facility on Saturday morning following a break in at the shelter in Weston.
RSPCA ACT said the team noticed Beau and Luna were missing after a forced entry into Tangos Cat Boarding Facility in the early hours of the morning.
Someone appears to have bent back a window frame before smashing the glass and gaining access to the facility, RSPCA ACT said.
CCTV footage appears to show one person was involved, with nothing else noted to be missing from the boarding facility.
An RSPCA worker was tasked with the unenviable job of calling the family of the cats to alert them they were missing.
RSPCA Chief Executive Michelle Robertson said the family was devastated.
Ms Robertson implored the cat thief to return them to the shelter or drop them off at a veterinary clinic so they could be reunited with their owners.
Ms Robertson said they'd never had an incident like this at the facility before.
"We've been in contact with our current clients that have cats with us, everyone we has spoken to has been incredibly gracious and we're very grateful for that," she said.
"Our facilities are safe and this is a really extreme measure in which entry was forced. Obviously someone was very intent on getting in."
ACT Police forensics were notified and launched an investigation on Saturday.
An ACT Policing spokeswoman confirmed on Sunday that officers were investigating the burglary.
"Anyone with information about the incident should call Crime Stoppers on 1800 333 000 or via www.crimestoppers.com.au quoting reference number 6777636. Information can be provided anonymously."
