Police were called to a report of a stabbing in Field Road, Forest Gate, where they found the victim had been attacked repeatedly, at 2.15pm today.
They arrested a man on suspicion of grievous bodily harm in connection with the attack. He remains in custody.
London Ambulance Service also attended and sent an air ambulance to treat the victim.
He was rushed to hospital where he remains in a critical condition.
Enquiries are ongoing.
Tags: Newham, Forest Gate