Saint Gayane Church is situated in the southern part of the city of Ejmiatsin, on the site where St. Gayane and two of her friends were martyred. According to Agathangelos, in 301 under the leadership of Gregory I the Illuminator and on the foundation laid by him, Trdat III the Great, his sister Khosrovidukht and the Queen Ashkhen built a Martyrium here. In 395 Sahak I Partev reconstructed the Martyrium of St. Gayane. In 630 Yezr I Parazhnakertatsi demolished the Martyrium and built on its place St. Gayane Church from smoothly hewn tufa, which stands up to this day. He also established a Monastic Congregation. St. Gayane Church is a four-pillar domed basilica with harmonious proportions and impressive interior. The vaulted mausoleum of the Saint virgin with its entrance from the south-eastern sacristy is situated under the High Altar.
In XVII century, the church was half-ruined and abandoned. XVII century historian Arakel Davrizhetsi writes that only the walls and the pillars on which the dome lies, were preserved. In 1652 Pilipos I Aghbaketsi completely rebuilt the church, restored its roof and dome. At the same time in order to protect the foundation of St. Gayane Church from groundwater, a drainage system was constructed from the southern wall of the Church to the field, so that the water could be used also for irrigation. In 1688 Yeghiazar I Ayntabtsi constructed the buildings of the Congregation of the Church, the wall, attached a three-arched gavit (narthex) hall to St. Gayane Church from the west, built chapels with liturgical tables dedicated to the Apostles Peter and Paul in its southern and northern sides. The gavit (narthex) hall later served as a sepulcher of Catholicoses.
In 1764, Simeon I Yerevantsi built a big underground icehouse in the territory of St. Gayane Church to store the food of the Church. During the reign of Gevorg IV Kostandnupolsetsi (1866-1882), Vahan Bastamyants - the Abbot of St. Gayane Church of Ejmiatsin renovated the church, built the western arched gate, the residential buildings for the abbot and congregants, the school, where he was a teacher. He also established a printing house and published the magazine “Dprots” (“School”). In 1910, the Armenian Community of Nor Nakhichevan brought a black granite tombstone for the grave of St. Gayane.
In 1959, St. Gayane Church of Ejmiatsin was renovated, the inside of the church was cleaned of plaster, the floor was tiled, the territory was improved, a mataghatun (house for oblation) and a drinking fountain (architect: R. Israyelyan) were built in the yard. In 1960, marble tombstones were placed on the graves of the congregants of the Mother See buried in the territory of the church after 1920. In 1976 the mound gathered during centuries around St. Gayane Church was removed, grout was injected into the walls and the decayed stones were replaced with new ones. In 1977-1980 due to the charity of Harutyun Mutafyan - an Armenian from London, the buildings of the Congregation of the Church were renovated and replenished with modern facilities, the roof and the dome were covered with stone tiles. The Catholicoses Yeghiazar I Ayntabtsi, Abraham II Khoshabetzi, Ghazar I Jahketsi, Minas I Aknertsi, Hakob V Shamakhetsi, Simeon I Yerevantsi, Ghukas I Karnetsi, Davit V Enegetsi, Matteos I of Constantinople are buried in the gavit (narthex) of St. Gayane Church of Ejmiatsin. And many archbishops, bishops, abbots, benefactor of the Mother See, ishkhans and other prominent people are buried in the territory around the church.
St. Gayane Church was listed as a UNESCO World Heritage Site in 2000.