Guy Fawkes' Night is the worst day of the year for household theft, revealed a survey from Norwich Union.
It said it received 25% more claims for theft from homes on 5 November than on an average day of the year.
Claims for household fires also increase for Bonfire Night, with Norwich Union receiving 50% more claims than usual due to firework-related incidents.
Simon Machell, customer services director for Norwich Union, said: "People don't tend to think about home security while they're enjoying themselves on bonfire Night."
"But it's the perfect opportunity for burglars who take advantage of the dark, the distraction and the noise of fireworks to take peoples valuables - often walking in through the front door because people haven't thought to lock it while they're busy with bonfires, barbeques and fireworks."
The Norwich Union Insurance Index also found that New Year's Eve was the second most risky day for homeowner.