The victim was found fatally injured in Walthamstow High Street, east London, late on Sunday night.
Paramedics fought to save him, but he was pronounced dead at the scene at around 11pm.
The Metropolitan Police said they were called to reports of a man stabbed at 10.25pm on Sunday night.
"He was pronounced dead at the scene," a spokesman said.
Much of the High Street was cordoned off on Monday morning, with forensic officers still searching the area.
The victim has not been identified.
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