The Reformed Theological Seminary (RTS) was established in 1971 initially as Reformed Theological College of Nigeria (RTCN). Prior to the establishment of RTCN, Nongo u Kristu u Ken Sudan hen Tiv (NKST), now called Nongo u Kristu u i Ser u sha Tar (NKST), that is, the Universal Reformed Church of Christ (URCC), trained its Pastors at the Theological College of Northern Nigeria (TCNN), Bukuru. TCNN was jointly established by the Tarayyar Eklesiyoyin Kristi a Sudan (TEKAS) Fellowship, the Dutch Reformed Christian Mission (DRCM) and the NKST to embrace the five branches of the Sudan United Mission (SUM) and the Church of Brethren Mission as members. TCCN took off on 9th February, 1959 with 22 students among whom were three NKST candidates: J. K. Manyam, I. D. Tija and D. K Anakaa. Only two candidates from the NKST namely Joshua Shimrumun Yakubu and P. P. Agba were admitted in the second set. Seven candidates were admitted in the third set: P. Y. Mom, D. J. Dzenda, Hembaor Gajir, J. A. Mayange, J. N. Nyamshar, S. I. Avungu and J. A. Gusha.
The low admission quota allocated to the NKST was a great impediment to the need for a large number of pastors to provide spiritual leadership for the converts. The NKST Synod had estimated that it required 70 additional pastors by 1973. The TCNN could not satisfy this need. The NKST found that it would no longer depend on TCNN to produce enough pastors for the growth of the church. Therefore, in 1966, the NKST Synod made a request to the Synod of the Christian Reformed Church (SUM-CRC) in North America to establish its Theological College. This request was turned down. Another request was made in 1968; yet it was rejected.
The NKST was not deterred by the refusal of the SUM-CRC of North America to approve the request to establish a Theological College. In 1970, the NKST Synod resolved to establish a Reformed Theological College where matured and committed Christians would be trained from a distinctively reformed perspective to meet the needs of the young but vibrant and fast growing church. Beside the low quota, the NKST frowned at some doctrinal issues enshrined in the training of pastors at TCNN. Therefore, in 1971, the Reformed Theological College of Nigeria (RTCN) was established at Mbaakpur, Shangev-Tiev, in Benue State, under the leadership of Mr. Iyortyom Achineku (later Rev. Dr. Iyortyom Achineku). It was officially declared open on February 13, 1971. The Theological College moved to its permanent site, Mkar in 1972.
Most of the NKST pastors are graduates of RTCN. The Seminary is affiliated to the University of Calabar and awards Degrees, Diplomas and Certificates in various fields of Theology. The first set of 16 students graduated in 1974. They were M. O. Adamu, J. U. Anmon, S. K. Arumunku, S. T. Gbagu, J. I. Guma, J. N. Hinga (past President, NKST Synod), P. K. Iber, N. A. Ingbian, P. K. Kuusu, J. V. Kwen, S. H. Kyuga, J. T. Mogen, J. A. Shimo, M. U. Ushi and J. A. Aduku. The annual intake of students has continued to increase over the years with students from various reformed churches across Nigeria and beyond.
The Bachelor of Theology degree offered at RTS Mkar was affiliated in 2001 with the University of Calabar; Cross River State. However, since the Bachelor of Theology Degree was not supervised by the National Universities Commission (NUC), graduates with the degree were denied acceptance into the NYSC scheme. For this reason, the Seminary sought for affiliation of the Bachelor of Arts in Religious Studies. In 2008, NUC and the University of Calabar made a resource verification visit to the Seminary to ascertain our suitability for offering the Bachelor of Arts in Religious Studies degree. Following the visit, the programme (Bachelor of Arts in Religious Studies) was consequently granted affiliation on April 20, 2010.