Investigators say six break-ins have happened since Sunday in the Old New Castle section.
They say the thieves gain access through unlocked windows and doors during the early morning hours.
Once inside, the culprits take purses and other items.
No one was hurt but police admit the thefts are a crime of opportunity.
"It's a simple remedy, I think sometimes, if people would just lock their doors, so we can avoid some of this, that may help," Lt. Adam Bram said.
Anyone with information on the burglaries is asked to call new castle police at 302-322-9800.