Rai Bahadur Sir Upendranath Brahmachari FRSM FRS (Bengali: উপেন্দ্রনাথ ব্রহ্মচারী) (19 December 1873 – 6 February 1946) was a leading Indian physician and scientist of his time. He synthesised Urea-Stibamine (carbostibamide) in 1922 and determined that it was an effective treatment for Kala-azar (Visceral leishmaniasis).