Dr Prasert Prasarttong-Osoth, the visionary founder behind Thailand’s largest private hospital network and a pioneering airline that helped elevate Koh Samui as a global destination, has died at the age of 93.
According to Bangkok Dusit Medical Services (BDMS), he passed away on Tuesday after receiving prolonged medical care for an undisclosed illness. Funeral rites are scheduled to take place at Wat Thepsirin in Bangkok.
Born in Bangkok on March 22, 1933, Dr Prasert was the fourth of ten children of Thongyu and Boonrod Prasarttong-Osoth, formerly known as Changboonchu.
He received his early education at Assumption College Bang Rak before continuing at Triam Udom Suksa School. He later enrolled in the pre-medical programme at Chulalongkorn University, completing his studies in March 1960.
After graduating in medicine from Siriraj Hospital under Mahidol University, he began his career as a surgeon at Siriraj Hospital, where he served for five years. Over time, however, his interests broadened beyond medicine, leading him into ventures in construction and oil exploration.
In 1972, Dr Prasert entered the healthcare sector by founding Bangkok Hospital, laying the foundation for what would later become BDMS. The company expanded steadily and was listed on the Stock Exchange of Thailand in 1991.
Today, BDMS operates the largest private healthcare network in Thailand and Cambodia, encompassing 58 hospitals under six brands: Bangkok Hospital, Samitivej Hospital, BNH Hospital, Phyathai Hospital, Paolo Hospital and Royal Hospital Group in Cambodia.
Leadership of BDMS was passed to his fourth daughter, Poramaporn Prasarttong-Osoth, who assumed the role of chief executive in September 2020.
Dr Prasert’s influence extended into aviation with the establishment of Sahakol Air in 1968 as part of his company Krungthep Sahakol, initially operating charter flights in response to market demand.
The airline was later spun off in 1984 as Bangkok Airways, and by 1986 it had launched scheduled domestic routes from Bangkok to Nakhon Ratchasima, Surin and Krabi using an 18-seat aircraft.
A major turning point came with the development of a privately owned airport on Koh Samui in Surat Thani.
The launch of Bangkok–Samui flights in 1989 significantly boosted tourism to the island, with the airline maintaining a dominant position on the route. Bangkok Airways was subsequently listed on the SET in 2014.
The carrier has since expanded its network to include both domestic and international destinations, linking Bangkok with key heritage sites such as Siem Reap in Cambodia, Luang Prabang in Laos, and several cities in China including Xi’an, Guilin, Jinghong and Chiang Rung.
Operational leadership of the airline is currently held by his eldest son, Puttipong Prasarttong-Osoth, who has served as chief executive since 2019.
In 2025, Dr Prasert ranked third among Thailand’s wealthiest stock investors, holding shares valued at 33.1 billion baht through a 9.2% stake in BDMS and an 11.4% stake in Bangkok Airways.
He was also listed by Forbes as the seventh-richest individual in Thailand, with an estimated net worth of approximately US$3.6 billion as of April 21.
Dr Prasert married Wanli Posayachinda in 1963. The couple had four children together and later adopted a fifth.
