Paramedics were called to reports of a stabbing on Brentford High Street at around 10.40pm on January 15.
A man was treated for knife wounds and taken to hospital.
His condition has been assessed not to be life-changing or life-threatening.
There have been no arrests.
A Metropolitan Police spokesperson said: “Around 23:00hrs on Thursday, 15 January, officers attended Brentford High Street after reports of a robbery.
“The victim was found at the scene suffering from knife injuries.
“He was taken to hospital, where his condition was assessed as non-life-changing and non-life-threatening.
“No arrests have been made, and police are making urgent enquiries.”
The London Ambulance service added: “We were called at 10.39pm yesterday (15 January) to reports of a stabbing in the High Street, Brentford.
“We sent ambulance crews, paramedics in fast response cars and an incident response officer to the scene.
“We treated a patient at the scene and took him to a major trauma centre.”
Anybody who witnessed the incident or has information is asked to call 101 and quote reference 7679/15JAN.