A pensioner was scammed by a man claiming to be from a care company.
The offender called at a house in Milton Street, Long Eaton, and said he wanted to fit an alarm and safe at the property.
He was allowed inside by the 81-year-old victim but during the visit stole two wallets and a large amount of cash.
The distraction burglar was white, aged between 30 and 40, about 5ft 7in, of medium build, clean shaven and with slicked back, dark hair.
He was wearing dark coloured plain overalls.
The offence took place at about 6.40pm on Wednesday.
Police want to hear from anyone who saw a man matching that description in the area.
Witnesses or anyone with information should call Derbyshire police on 101 or Crimestoppers on 0800 555 111.