The Kerala State Road Transport Corporation began as the Travancore State Transport Department, constituted by the former Travancore Government with the intent of reorganizing the transportation services of the former state. Mr. EG Salter, Assistant Operating Superintendent of London Passenger Transport Board, was appointed as Superintendent of the Transport Department on 20 September 1937. The Travancore Transport Department grew with nationalisation of key interstate routes such as Thiruvanathapuram to Kanyakumari and Palakkad to Coimbatore.
The first fleet consisted of 60 Comet chassis fitted with Perkins diesel engines, imported from England. The bodies of the buses were built by the staff of the Travancore State Transport Department under the supervision of the Superintendent. The model for the selection of operating staff continues to be followed by the current operating staff. The Transport Department gave preference in recruitment for those who were likely to lose their the private transport company jobs resulting from the nationalization of ThiruvanathapuramKanyakumari route. Thus the Transport Department began with a staff of about a hundred graduates appointed as Inspectors and Conductors.
The State Motor Service was inaugurated by His Highness Sree Chithirathirunal on 20 February 1938. His Highness and his kin were the first passengers of the system on the inaugural trip; Superintendent Salter was the driver of the bus. This bus, along with the thirty-three other buses brought on road driving through the Kowdiar Square was an attraction at that time.
Following the enactment of the Road Transport Corporation Act in 1950, the Government of Kerala formulated KSRTC rules in 1965 by Section 44. The Transport Department was converted into an autonomous corporation on 1 April 1965 and the Kerala State Road Transport Corporation was formally established by the government of Kerala by the notification dated, 15 March 1965.
For all KSRTC Buses the registered under a separate RTO at Thiruvanathapuram having registeration series