Introduction. The Evangelical Reformed Church of Lithuania as a united Reformed Church organization and Reformed Church province of Lithuania can be counted from the year 1557 at the Synod in Vilnius on December 14th of that year. From that year the Province (also can be called General or National) Synod met regularly forming all the church provinces (district Synods) of The Grand Duchy of Lithuania. Started from two and later growing to six districts and representative district synods with leading elder pastor – superintendent (senior). The abbreviated name for the church is in Latin, Unitas Lithuaniae (shorter-UL) or in Polish, Jednota Litewska (Union of provincial Church of Lithuania). It sent its representatives to the Polish -Lithuanian Commonwealth (Rzeczpospolita) General Synods with representatives from 3 provinces: Minor Poland (Malopolska Jednota), Maior Poland (Wielkopolska Jednota) and Lithuania (Jednota Litewska). However in it's administration UL was in fact a self-governing Church. The first Superintendent of the church was Rev. Simonas Zacijus (Szymon Zacjusz, approx 1507-1591). In 1565 the anti- Trinitarian Lithuanian Brotherhood who rejected the doctrine of the Trinity separated from UL. The UL parish network covered nearly all of The Grand Duchy of Lithuania. Its district centers were Vilnius, Kedainai, Biržai (today - Lithuania), Sluck, Kojdanov and Zabludov later Izabelin (today - Belorussia). The Church in Lithuania grew weaker due to the effects of war and the counter-reformation. Up until the Second World War, The Reformed Church in Lithuania had about 10,000 believers. Now the Church has over 7,000 believers with parishes in Biržai and Biržai region and Kėdainai (the historical area of Duchy of Radziwiłłs) , Klaipėda (area of former Prussia was called as Minor Lithuania) and Vilnius (the capital of Grand Duchy of Lithuania), and the other large towns (Šiauliai, Panevėžys and Kaunas). The UL has, since 1922-1925, been a World Alliance of Reformed Churches (now World Communion of Reformed Churches) and also maintained relations with the Reformed Churches in Germany, Switzerland, France, Poland, Hungary, Sweden, Scotland, the Netherlands and The U.S.A. The Highest institution of The UL is the Synod consisting of the pastors (kunigai), catechists called also deacons (katechetai, diakonai), the secular, senior curates (kuratoriai) and delegates (delegatai) from the evangelical reformed congregations. An inter Synod institution works during the time between Synod assemblies in Biržai consisting of the Consistory and the senior minister, the Church (General) Superintendent. Ministers are trained in the University of Klaipėda and abroad.