According to officials, Bahman Golbarnezhad fell during the race, and and died on his way to the hospital.
“He unfortunately passed away,” International Paralympic Committee (IPC) spokesman Craig Spence said.
“The athlete received treatment at the scene and was in the process of being taken to the athlete hospital when he suffered a cardiac arrest,” the IPC said in a statement.
“The ambulance then diverted to the nearby Unimed Rio Hospital in Barra where he passed away soon after arrival.”
Medics who arrived at the scene revealed his “helmet was seriously damaged” and he had suffered “grave head trauma,” according to Rio 2016 communications manager Mario Andrada.
The incident was the first time an athlete would die at a Paralympic games. This is according to Sir Phillip Craven of the IPC.
“Our hearts and prayers are with Bahman’s family, his teammates and all the people of Iran,” president of Brazil’s Olympic Committee Carlos Nuzman said. He also added that it was “very sad news for sport and for the Paralympic movement”.
The Iranian flag has been lowered to half mast. There will also be a minute of silence at Sunday’s closing ceremony.