Nairobi Traffic Commander Edward Mwamburi confirmed the deceased was the driver of the matatu.
The 7am accident happened when the matatu collided head on with an oncoming saloon car that had joined the road abruptly.
Mwamburi said the saloon car had earlier on been involved in another accident at the scene and was getting out of the ditch into the road when it collided with the matatu.
According to Kenya Red Cross, the injured were evacuated and treated at the Kenyatta National Hospital.
KRC Communications Manager Arnolda Shiundu said that the casualties were evacuated through concerted efforts between their EMS_Kenya ambulances and those from the Kiambu County and Nairobi City County.
“The occupants who were in the private car suffered injuries together with those in the matatu. They all sustained injuries and rushed to Kenyatta National Hospital,” she said.