One person has been taken to hospital in a serious condition following the incident, which happened at around noon.
Filsham Road in St Leonards is closed from the junction with St Saviour’s Road to the junction with Bexhill Road.
A spokesman for South East Coast Ambulance Service said: “Ambulance crews attended the scene following reports of a road traffic collision at approximately noon.
“One patient has been treated at the scene and was recently taken to Conquest Hospital in a serious condition.”