The Senate (Polish: Senat) is the upper house of the Polish parliament, the lower house being the Sejm. The history of the Polish Senate stretches back over 500 years; it was one of the first constituent bodies of a bicameral parliament in Europe and existed without hiatus until the final partition of the Polish state in 1795. The contemporary Senate is composed of 100 senators elected by a universal ballot and is headed by the Marshal of the Senate (Marszałek Senatu). The incumbent Marshal of the Senate is Małgorzata Kidawa-Błońska.
Following a brief period of existence under the Second Polish Republic, the Senate was again abolished by the authorities of the Polish People's Republic. It was not re-established until the collapse of the communist government and reinstatement of democracy in Poland in 1989. The Senate is based in Warsaw and is located in a building which forms part of the Sejm Complex on Wiejska Street, in close proximity to the Three Crosses Square and Ujazdów Castle.