Police were called around 9.30pm to a fight in Whatebone Lane South and attended along with the ambulance service.
A man aged in his 20s had been stabbed and was taken to hospital where his injuries were decided to be neither life-threatening nor changing.
Before the emergency services arrived, the suspect had fled the scene and is yet to be found.
Police officers are making “urgent” enquiries in an effort to find him and have asked anyone with information to contact them.
This can be done through 101 with reference 7317/05APR.
The London Ambulance Service was also contacted for details but is yet to respond.
A Metropolitan Police spokesperson said: “Around 21:35hrs on Saturday, 5 April, officers attended Whalebone Lane South, Dagenham, alongside the London Ambulance Service following reports of an altercation.
“A man in his 20s was treated at the scene for stab injuries.
“He was taken to hospital, where his injuries were assessed as non-life-changing and non-life-threatening.
“The suspect left the scene before emergency services attended, and police are making urgent enquiries to locate him.
“Anybody who witnessed the incident – or who has potentially relevant information – should contact police on 101, quoting reference 7317/05APR.”
