The settlement was first mentioned in 1278, under the name of “Dychen Sent Martun”, the current name of Târnăveni being adopted and formalized by a decree issued in 1941. Ever since the Middle Ages, vineyards covered a significant part of the cultivated land, so the area was known as the “wine Country” (Weinland). Due to its location, the city of Târnăveni was under the influence of some major county.
During World War II, the Jewish community was decimated as part of the Holocaust, and the synagogue closed down. 230 Romanian soldiers, after Romania parted with the Axis and joined the Allies in 1944, defended the city against German troops.
After the war, the industry of Târnăveni witnessed a continuous development. In 1957, for the first time in Romania, polychlorinated vinyl was produced.
On 5th November 1998 Târnăveni became a municipality.