Police were called at 1919hrs on Saturday, 20 April to reports of a fight between two males at Osborn Street, E1.
Officers attended along with London Ambulance Service [LAS]. At the scene, two males had suffered knife wounds.
The injured men were taken by London Ambulance service to separate London Hospitals.
A male, aged 20s, is in a life-threatening condition.
A male, aged 40s, his condition is not life-threatening.
He has been arrested on suspicion of attempted murder. Officers from Tower Hamlets investigate. Enquiries continue.
Anyone who witnessed this incident or has information is asked to call police on 101 quoting CAD6392/20APR,