It is the oldest Jewish monument in Romania and it was built in the years 1657-1671 at the initiative of Rabbi Nathan Hanover who served in Iaşi since 1651. In the old Hebrew neighborhood of Targul Cucului, there is a Synagogue street. A charter of Alexander Iliaş from 1686 granted to the guild of Iasi Jews strengthened their right to have a synagogue. On the south wall an inscription states that the Great Synagogue was restored in 1761, when it had about 50 parishioners. In 1862 a fire destroyed the woodwork and paintwork, which were subsequently restored. The Great Synagogue of Iasi has a loft floor above the porch reserved for the women. The coexistence of Sephardic and Ashkenazi decoration items indicates the presence of both rites. Its overall makeup is unique in Romania. From the outside the building has bold volumes. Over a tall ground floor, limited by a small cornice, a covered inverted boat shaped transverse structure stands at the west end and at the other end there is a great dome. The small openings of windows and doors on the large exterior painted walls and their thickness remind one of the fortress synagogues in Poland.
The interior architecture is influenced by the synagogues of Eastern Europe. The large congregation hall is divided in two and includes BIMA with AMUD for celebration, decorated with two winged animals, woven with gold wire.