Allowah, originally known as the Allowah Babies Hospital, was first established in 1954 in a house at Artarmon in the Northern Suburbs of Sydney. It relocated to its present site in Dundas in 1976 and has been operating continuously since that time. 

In the early 1980's it was purchased by Phillip Jacoby and his family whose vision was to see it provide medical and respite care and a quality of life to children with severe disabilities. After his death it was put on the market and remained there for three years. His family did not want to sell to developers and were very pleased to sell to the Presbyterian Church in February 2004 to enable the hospital to remain functioning.

The existing building in Dundas was originally built for children under the age of two, and licensed for 45 beds/cots. With improved medical, nursing, and therapeutic intervention, children with disabilities now have greater life expectancies and improved quality of life. Allowah now cares for children and young people up to the age of 16 years, resulting in the present building being inadequate. The children need areas for living, dining, leisure, bathing, and sleeping. See the Redevelopment Page for more details.