Over 33 other people were injured in the accident that occured shortly after 5PM.
Witnesses say the two buses belonging to one company, Nyamira Express collided head-on.
According to Keroka traffic police boss Abraham Ndegwa, the accident occured near Metamaywa shopping centre.
One of the buses was heading to Nairobi from Kisii while the other was going on the opposite direction.
According to an eye witness, the driver of one of the buses died on the spot.
The injured passengers were rushed to Keroka district hospital and Kisii level five hospital where they are receiving treatment.