[2] The hospital was founded in 1937 with funds provided Captain Thomas Hall, a merchant seaman, and was operated by Dr. Ralph Waddell, his wife Ellen, Mr. Pleng Vitiamyalaksna and Pastor Kon Vui-leong.

With the Japanese invasion of Thailand during Second World War, the Annex was closed, and all missionaries fled the country for their safety.

However, part of the clinic continued its operation under the direction of Mr. Pleng, a medical assistant, and Dr. S. Bene, a Romanian physician.

On the hospital's 50th anniversary in 1987, the Pleng Vitiamalaksna building was added to provide beds for Obstetric and Pediatrics, along with some auxiliary services.

[3] In 1990, Mission Health Promotion Center, capable of housing 60 people, was launched in Saraburi Province, north of Bangkok.