Three houses in Calcot and one in Tilehurst have been targeted by burglars, with a car, laptops and handbags among the items stolen.
Police are linking the four burglaries, which took place on March 27 and 29.
The first was between midnight and 6am in Fairway Avenue in Tilehurst on March 27.
The other three were between the same times on March 29 in Calcot, at houses in Dunoon Close, Corsham Road and Narromine Close.
A blue Vauxhall Corsa was stole, along with handbags containing cash and bank cards, laptops, and a satnav.
Investigating officer Det Con Andrew Philpott, of Newbury Local CID, said: “Entry was gained through letterboxes so please ensure that all doors are locked and the key removed, even if you are not at home.
“I am encouraging anyone who has any information about these incidents, or has seen anyone acting suspiciously around the Calcot or Tilehurst area, to get in touch by calling the non-emergency number 101.”
In response to the burglaries, the police have issued some security measures residents can take to reduce the risk of break-ins.
These include installing a visible burglar alarm, keeping valuables and keys out of sight and out of reach of doors and windows, and storing high-value items in a safe.
They also recommend not leaving spare keys in obvious places, fitting a door chair and spyhole and keeping items that could be used in a burglary.