The man, aged in his 70s, was discovered in the water near Harrington Hill in Hackney on Wednesday afternoon.
His death is being treated as unexplained, but not suspicious. His next of kin has been informed.
Enquiries into the circumstances are ongoing, a Met Police spokesman said.
He added: “Police were called at approximately 1:39pm on Wednesday, March 17 to reports of a body in the River Lea, near Harrington Hill in Hackney.
“Officers attended along with London Ambulance Service and the London Fire Brigade.
“A man in his 70s was pronounced death at the scene.”