The victim was not injured in the incident.
The victim, a 49-year-old man, was walking along Saint Ives Lane at about 10am last Sunday when he stopped to tie his shoe lace.
As has was doing this, a man came up behind him and locked his arms behind him. Two other men then stood in front of the victim.
One of them pulled out a small pocket knife and threatened the victim with it. The others then went through the victim’s pockets and stole cash from him. The three offenders then fled in the direction of Main Street.
The first offender is about 5ft 11ins tall with a thin build and was wearing a black hooded top and black trousers.
The second offender is about 5ft5ins tall with a slim build, and was also wearing a black hooded top, dark trousers and dark coloured gloves.
The third offender is about 5ft 11ins tall with a stocky build, was dresses all in black including gloves.
All three of them were aged between 18-20 and all had their faces covered.
Investigating officer, PC Lorraine O’Connor, based at Abingdon police station, said: “I am looking for witnesses to this incident, which resulted in a man being robbed at knifepoint.
“If you can help, please get in touch. You can do this by calling 101 and quoting reference number 43210411277, or by call calling Crimestoppers anonymously on 0800 55 111. Alternatively, you can make a report online.”