Ten mobiles phones are being stolen every day in the county.
The police figures, exclusively revealed to the Evening Telegraph, show 11,500 mobiles have been stolen from Northamptonshire residents in the past three years.
They show the numbers of thefts have been decreasing steadily each year but there have still been 4,219 mobile phone thefts in the north of the county, which includes Kettering, Wellingborough, Corby and Rushden, since 2006.
Crime prevention officer Paul Golley said people weren't doing enough to protect themselves from thieves and against robbery.
He said: "We'd urge people not to show off their mobile phones or leave them unattended in public places like pubs and restaurants. People are advised not to use them while walking in public places as you are more prone to robbery.
"We'd remind motorists not to leave phones in their cars and people should switch their phones to vibrate if they think their phone might bring them unwanted attention."
Mr Golley added Northamptonshire police have been helping to reduce the problem by promoting forensic property marking schemes, encouraging people to use the security features on their phones and advising people to register their phones on www.immobilise.com.
The number of mobile phone thefts in north Northamptonshire stood at 1,482 for the period 2006 to 2007. In the following year they dropped to 1,446 and the latest annual figure was 1,291.
The Immobilise website, which Northamptonshire police promote, is the UK's National Property Register. It is a free service used by the public and businesses to record their possessions and company assets.
All police forces use it to trace owners of lost and stolen property.