Ottomar Ernst Felix Rosenbach (4 January 1851 in Krappitz, Silesia – 20 March 1907) was a German physician. Krappitz was a Silesian city where his father, Samuel Rosenbach, practised medicine. He received his education at the universities of Berlin and Breslau (M.D. 1874). His studies were interrupted by the Franco-Prussian war, in which he took an active part as a volunteer. From 1874 to 1877 he was assistant to Wilhelm Olivier Leube (1842-1922) and Carl Wilhelm Hermann Nothnagel (1841-1905) at the medical hospital and dispensary of the University of Jena; in 1878 he was appointed assistant at the Allerheiligen-Hospital at Breslau, and became privatdozent at the university of that city; in 1887 he became chief of the medical department of the hospital, which position he resigned in 1893;