Burglars allegedly told homeowners they were police officers after breaking entry through a back conservatory door.
Two men gained entry to the home Orchard Close in Shiplake Cross before carrying out a search of the house.
But Thames Valley Police has said the men ran into the owner.
The men told the owner they were police officers and told them to "stay calm".
Thames Valley Police said jewellery and cash were stolen and the force is appealing to residents to check CCTV footage of the area between 10.30pm to 11pm on Friday (September 17).
A Thames Valley Police spokesman said: "Priority Crime Team, Abingdon are appealing for witnesses to an incident of burglary in Shiplake.
"We are requesting residents to review any CCTV, doorbell and dashcam footage."
If you have any information or footage call 101 and quote the reference number 43230415483.