Niels Thorkild Rovsing (1862 to 1927) was a Danish surgeon. His eponyms include the Rovsing sign of acute appendicitis, the Rovsing syndrome (abdominal pain in a horseshoe kidney), the Rovsing operation I (for polycystic kidney), and the Rovsing operation II (to separate a fused "horseshoe" kidney). He received his M.D. degree in 1885 and his Ph.D. in 1889 from Copenhagen University. Rovsing practiced surgery from 1892 to 1902 at the Queen Louise Children's Hospital and the Red Cross Hospital, both located in Copenhagen. He became Professor of Surgery in 1899 and Director of Surgery at the Royal Frederiks Hospital in 1904. Rovsing earned international recognition for his innovative urological surgery. Together with his colleague, Eilert A. Tscherning, Rovsing founded the Danish Surgical Society (Dansk Kirurgisk Selskap) in 1908. His advocacy for antisepsis and Listerism advanced his notoriety and exemplified his medical leadership. His clarion call for a modern hospital led to the construction of the Copenhagen University Hospital (Rigshospitalet) that opened in 1910. Rovsing was an Honorary Member of the Edinburgh Medico-Chirurgical Society and the Association of Surgeons of Great Britain and Ireland. Rovsing served briefly as Denmark's Minister of Education in 1920. He died in 1927 from cardiac failure and laryngeal cancer.