Dai Roberts, 39, from Carmarthen in Wales, died at the scene after emergency services were called at around 10:50.
Driver, James Williams, 27, was taken to the Royal Infirmary of Edinburgh with serious, but not life-threatening, injuries.
The remainder of the closed-road event, held near Duns, was cancelled along with the Reivers Rally, scheduled for Sunday.
In a team statement, James Williams Rallying said: “It is with a heavy heart, we have to share this sad news. “The motorsport community is deeply saddened to learn of the passing of our beloved Dai Roberts. “Our thoughts and prayers are with the Roberts family at this difficult time.”
His brother Gareth died competing in a rally in Sicily in June 2012. Police Scotland said that no-one else was injured in the crash.
Motorsport UK gave out a statement earlier today – “It is deeply saddened to announce that co-driver Dai Roberts lost his life in an incident at the Jim Clark Rally on Saturday 24 May 2025.
Driver James Williams was taken by ambulance to the Royal Infirmary of Edinburgh with serious but not life-threatening injuries.
Motorsport UK sends its condolences to Dai’s family and friends, the Jim Clark Rally, Jim Clark Memorial Motor Club and members of the motorsport community.
Motorsport UK has initiated a full investigation into the circumstances of the incident and will work closely with the Jim Clark Rally event organisers and Jim Clark Memorial Motor Club and will cooperate with the relevant authorities.”
