| month | year | |
|---|---|---|
| February | 1950 | Opening of the Yao city citizens hospital at 2-1-55 Minami Taishido Yao city (5 departments, 32 beds). |
| February | 1953 | Named changed to Yao municipal hospital. |
| September | 1980 | Completion of the South building extension (380 beds for general diseases, 66 beds for infectious diseases patients) |
| April | 2003 | Clinical training hospital |
| May | 2004 | Opening of the new hospital at 1-3-1 Ryugecho Yao city (16 departments, 380 beds) |
| August | 2004 | Japan Council for Quality Health Care's Hospital Evaluation Standard accredited hospital |
| November | 2007 | Osaka prefecture perinatal medical center certification |
| July | 2008 | DPC applying hospital |
| November | 2008 | 18 department, 380 beds |
| February | 2009 | Establishment of "Yao Municipal Hospital Reform Plan" |
| April | 2009 | Transition to apply the local public corporation act, appointment as Osaka cancer treatment base hospital |
| August | 2009 | Japan Council for Quality Health Care's Hospital Evaluation Standard ver. 6.0 |
| March | 2011 | 20 departments, 380 beds |
| February | 2012 | Establishment of "Yao Municipal Hospital Management Plan (2012-2014)" |
| April | 2012 | 21 departments, 380 beds |
| November | 2012 | Regional Medical Support Center Approval |
| April | 2015 | Appointed as an associate base hospital of regional cancer treatment |
| June | 2017 | Won the Excellent Municipal Hospital Award (National municipal hospital founder council and the national municipal hospital council chairman awards) |
| November | 2017 | Won the Excellent Hospital Award of the National public hospital federation |
| June | 2018 | Won the Excellent Municipal Hospital Award (MIC awards) |
| August | 2019 | Approved in the function evaluations of the Japan Council of Quality Health Care |
| March | 2020 | New installation of emergency CT scanner |
| April | 2021 | Three new departments (Psychiatry, Gastroenterological Surgery, and Respiratory Surgery) were added to the existing 21 departments, bringing the total to 24 departments. |
| March | 2022 | The Regional Medical Liaison Center and the Admission/Discharge Support Center were relocated to the first floor. |
| September | 2023 | Started gastric cancer screenings (gastroscopy) |
| April | 2024 | Launched online identity verification using My Number Cards |
| April | 2024 | Launched postpartum care services (Launch date TBD) |
