Six fire engines and around 40 firefighters were called to a fire at a stables on Hall Lane in Upminster.
A single storey stable block was destroyed by the blaze. One horse was led to safety by a member of staff before the arrival of the Brigade. Two horses sadly died at the scene.
The Brigade was called at 0439 and the fire was under control by 0546. Fire crews from Harold Hill, Hornchurch, Romford and Dagenham fire stations were at the scene.
The fire has been recorded as undetermined, thought to have been caused by either an electrical failure or self-heating event.