Around £500 in cash has been stolen during a raid on a village home some time on Christmas Eve or Christmas Day.
The house in Field End, Storrington, was targeted between 7pm on December 24 and 1am on December 25.
It is believed the offenders entered the property via a back door.
Officers from Sussex Police have released a witness appeal.
PCSO Emma Walsh, of Horsham police, said the occupants appeared to have been out at the time of the burglary.
She said: “We would like to hear from anyone with information about this incident. Please contact Sussex Police on 101 quoting serial number 0102 25/12/13 or independent charity Crimestoppers anonymously on 0800 555 111.”