The people were travelling in a tempo (mini bus), which collided with a truck on the state highway.
"The accident occurred around 6 am on the outskirts of Kamlapur village near Periyapatna (about 50 km from Mysore) when the two vehicles collided due to negligence and over-speed," Mysore District Superintendent of police Abhinav Khare told IANS from the accident spot.
Three children and three women were among those killed in the accident
Six people, who were also on board in the ill-fated tempo, suffered injuries and were rushed to state-run hospitals at Hunsur and Mysore for emergency treatment.
"The tempo driver died on the spot, while the truck driver survived. We have arrested him for investigation and registered an accident case against him," Khare said.
The truck was hired by the state-run Bharat Petroleum for transporting gas cylinders from Mangalore to other parts of the state and to Tamil Nadu for across-the-border distribution.
Khare added that the victims were returning to Mangalore from Tamil Nadu after a vacation.