An 80-year-old taxi driver was thrown to the ground by two men and robbed of a bag containing around £200, a sat-nav and a mobile phone.
The attack happened in The Plain, Epping, when the pensioner was coming to the end of his shift shortly before 1am on Thursday.
One of the attackers is described as being in his mid-20s, approximately 5ft 10ins and wearing a motorcycle helmet.
Investigating officer, Detective Constable Nicola Hudson, said: "We’re hoping someone may have seen his two attackers run along the B181, Epping Road.”
The victim, from Epping, sustained a minor hand injury and did not require medical treatment.
Anyone with information can contact detectives at Loughton police station on 101 or call Crimestoppers anonymously on 0800 555111.