A man had his mobile phone and £60 cash stolen from him after he was robbed at knifepoint on Sunday, October 13.
The robbery happened between 5am and 5.15am in Violet Close, Corby.
The 23-year-old victim was walking to work when he was approached by a man with a knife, who threatened to hurt him if he did not give him his property.
The victim gave the offender about £60 in cash and a mobile phone.
The offender is described as a white man, aged 20 to 23, 5ft 11in, short brown hair and with a medium build.
He was wearing a dark hooded top with a zip and dark bottoms with a double white line down the legs. He spoke with a Corby accent.
Witnesses, or anyone with information, should phone Northamptonshire Police on 101.
Alternatively, information can be given anonymously to Crimestoppers on 0800 555 111.