The hospital will be running a year-long calendar of events as part of the celebrations, which will kick off in April.

The hospital officially opened on September 4, 1889 as the Berrima District Cottage, which was later changed to Bowral and District Hospital in 1919.

Over the years the hospital has transformed from a humble cottage to a large facility offering a range of general and specialised services.

Construction of the hospital was first discussed at a public meeting in 1885 of people from Berrima, Bowral, Mittagong and Moss Vale. Opinions were divided on the hospital and there were some objections, including a letter in the Bowral Free Press voicing local concern about infectious patients "driving visitors away and ruining the district".

However, support for a hospital in the district increased and the Berrima District Cottage Hospital was officially opened on 1889, which was declared a public holiday.

The original design had accommodation for six patients, four male and two female beds. The male and female wards were each overlooked by an inspection window from the matron's bedroom and were well separated.

Bowral and District Hospital general manager Alison Derrett said she felt very fortunate in her position during such an important time in its history.

"Like the Wingecarribee community, the hospital has grown and changed over the past 125 years," Ms Derrett said.

"Ten years after it opened the hospital was treating 115 patients, including 14 accident patients and 35 operations.

"Today our staff deliver around 450 babies each year, treat more than 17,500 patients in the emergency department and undertake more than 2700 operations.

"Throughout its 125 years the hospital has received strong community support and continues to enjoy this support today from groups like the Hospital Auxiliaries, the BDCU Children's Foundation, the strong volunteer community, and the University of Wollongong."

The Hospital is kicking off celebration events in April with a lecture by former hospital matron Nancy Reynolds and a presentation by Dr Simon Grant. Dr Grant is a senior staff specialist and will share his interest in plants, specifically rare and exotic maple trees and medicinal plants including the opium poppy and camellia.

The lecture will be held at 8am on Wednesday, April 2 in the Old Hospital Lecture Room and a flag raising ceremony will follow.

Other celebrations include a restored quilt display, refurbishment of the hospital gardens, a staff awards night and an art competition for local schools with dates yet to be announced.