The incident happened in Nottingham Road just before 1.30am today (May 30).
Officers and London Ambulance Service crews attended and found a man injured.
He was treated at the scene before being taken to hospital where his condition is currently unknown.
A crime scene has been put in place.
No arrests have been made following the incident.
A spokesperson for Metropolitan Police said: “Police were called to Nottingham Road, Croydon, at 01.27hrs on Tuesday, 30 May to reports of a stabbing.
“Officers attended along with paramedics from London Ambulance Service (LAS). A 24-year-old man was found with stab injuries.
“He was treated at the scene before being taken to hospital. We await an update on his condition.
“A crime scene has been put in place. There have been no arrests.”
