A 19-year-old man was discovered by emergency services with multiple stab wounds in Harold Hill.
Officers were called just before 4.40pm on Saturday (August 28) to an "injured male" at the junction of Barberry Close and Myrtle Road.
They attended, along with London Ambulance Service and London's Air Ambulance, and found the man with "multiple stab wounds".
The teenager was taken to hospital and police say his condition is not life-threatening.
A Met spokesperson said: "Two men were arrested nearby on suspicion of attempted murder and taken to a police station for questioning. They have been released on bail to a date in September.
"Enquiries are ongoing to establish the circumstances."
Anyone with information is asked to call 101 quoting CAD 4845/28Aug.
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