A 21-year-old man was robbed as he walked along Ibsen Court, Corby, on Saturday (December 22).
The incident took place at about 7pm, when the man was approached by two men.
A police spokesman said: “One of the offenders pushed the victim against a wall, threatening him and demanding that he empty his pockets.
“The offenders stole the victim’s mobile phone and also took cash and other documents from the victim’s wallet.”
Both of the offenders were described as white men, of slim build and aged about 25.
One offender had brown eyes and wore a black hooded jumper and a dark baseball cap.
The other man wore a white hooded jumper with white tracksuit bottoms.
Witnesses to this incident, or anyone with information about it, can call Northamptonshire Police on 101 or information can be given anonymously to Crimestoppers on 0800 555111.