| 1901 | The first elevator was installed, with funds raised by the Co-Operative Society |
| Benjamin Knox Rachford, named chair of Pediatrics at UC College of Medicine | |
| November 18, 1903 | Chapel dedicated |
| 1904 | A new wing was added to the second hospital building |
| February 1, 1906 | Training school for nurses opened |
| 1907 | First X-ray machine at Children's Hospital |
| 1908 | Ohio Medical College merges with Miami Medical College to form the Medical College of the University of Cincinnati |
| 1908-1914 | Arch Carson, M.D., president of the Medical Staff |
| 1909 | Babies Milk Fund was established to provide 'certified' milk to infants and children |
| 1911 | Junior Co-Operative Society established |
| 1913 | Housemother hired to direct all social, moral, and devotional matters |
| William Cooper Procter joins the Board of Trustees | |
| 1915 | The nurse training program expanded to two years |
| 1916 | Electric lights were installed throughout the hospital as a gift from the Junior Co-Operative Society |
| 1919 | Ethel Winston, M.D., first resident physician |
| October 4, 1920 | Mary Emery endows pediatric chair in honor of Benjamin Knox Rachford, M.D. |
| 1921 | William Cooper Procter named President of the Board of Trustees |
| July 5, 1921 | Medical staff approves organizational changes: new Board of Trustees established; name changed to Children's Hospital |
| 1922 | First constitution and bylaws of the Medical and Dental Staff |
| Kenneth Blackfan, M.D., named the first B.K. Rachford Professor of Pediatrics | |
| 1923 | First Grand Rounds |
| Accreditation as a Class A children's hospital | |
| Planning begins for constructing a new hospital | |
| 1924 | Albert Graeme Mitchell, M.D., named second B.K. Rachford Professor of Pediatrics |
| 1926 | Pediatric residency program officially recognized |
| August 6, 1926 | An affiliation agreement with the University of Cincinnati College of Medicine signed |
| November 18, 1926 | Third hospital building, located at Elland and Bethesda Avenues, dedicated |
| December 6, 1926 | The third hospital building officially opens |
| 1928 | Vincent Hall (nurses' dormitory) opens |
| January 4, 1928 | William Cooper Procter announces $2.5 million gift to construct and endow the Children's Hospital Research Foundation (CHRF) |