The victim, thought to be in his 30s, was found with stab wounds to the chest at a property on High Road, Leyton.
Scotland Yard said it had arrested a 34-year-old man shortly after the attack on suspicion of murder. He currently remains in custody.
Police said it was believed the two men were known to each other. A post-mortem examination is due to take place later.
A murder arrest has been made following a fatal stabbing in east London overnight.