Sunao Tawara (田原 淳 Tawara Sunao?, July 5, 1873 – January 19, 1952) was a Japanese pathologist known for the discovery of the atrioventricular node.
Tawara was born in Ōita Prefecture and studied at the Medical School, Imperial University of Tokyo in Tokyo, graduating in 1901 and receiving his Doctorate of Medical Science in 1908. Between 1903 and 1906 he spent in Philipps University of Marburg in Marburg, studying pathology and pathological anatomy with Ludwig Aschoff. It was here he undertook his important works on pathology and anatomy of heart. Upon returning to Japan he was appointed assistant professor of pathology at Kyushu Imperial University in Fukuoka, obtaining full professorship in 1908.
Tawara's monograph, "Das Reizleitungssystem des Säugetierherzens" (English: "The Conduction System of the Mammalian Heart") was published in 1906.
To honor his achievements, Kyushu University named a road Tawara Street.