Acomparative study on Western and Armenian CHURCH architecture, will give us precious information about the CHURCH early architecture. Armenian CHURCH is a sample of Christian architecture on Eastern context. This study will show that the two architectural cultures do not have the same origins, did not go through the same development process and are not common in dominant structures. Each of these two emanates from its historical and cultural context. Regarding this, the architecture of Western CHURCH mostly follows the Greco-Roman architecture and the Armenian one goes back to its own origins, beginning from Urartian period and even before. When talking about early architecture of CHURCH, one should notice that, despite of presenting both the linear and the central structures, Western CHURCH mostly obeyed the linear one. This geometrical structure was also dominant in pre-Christian period and was named the Christian Basilica afterwards. In contrast, Armenian CHURCH payed more attention to central structures, coming out of local Urartian and pre-Christian temples and going back to elder local housing prototypes. Central structures, limited to Roman and Byzantine round mausoleums and similar CHURCHes in West, are noticeably in focus of attention when studying Eastern architecture. However, the linear CHURCH types were wide spread in Armenia only at the beginning of CHURCH architecture (4th to 7th centuries) in two general types. The single nave or hall CHURCH goes back to Urartian and pre-Christian local temples and resembles them in dimensions as well as the other characteristics, and the three-nave hall or basilica, having some occasional features in common with the Syrian one, generally goes back to Urartian gathering halls. Thus, even the so-called basilica in Armenian CHURCH architecture has not the same origins with the Western one and should be conceived as an original CHURCH type, specially noticing its priority in time, for almost 25 years. Coming to central structures in Armenian architecture which are also the most developed and widespread types, one can see that being built from the beginning of forth century this genotype has merely local priors, both in shape of Urartian Square Temple and a central semi domed space in local houses. The latter prototype existed at least from the 5th millennium BC and was very typical of Urartian period. The central structures in Armenian CHURCH architecture can also be associated with the Eastern, mostly Iranian, fire temples. Besides the linear and the central structures in early CHURCH architecture there are some mixed and crucial types which belong to Byzantine period according to the most world architecture history sources. Studying the architecture of the same period in Armenia shows that the prior sample of the most famous types, as are the central domed CHURCH, the domed basilica, and the cross-in-square CHURCH with five domes, was created in Armenia in Tekor Cathedral (478 AD), Ejmiadzin Cathedral (301 AD) and the Avan Cathedral (6th century) in turn. Thus, the named CHURCH types, including the last as genotype of Eastern Orthodox CHURCH from Greece to Russia, should be recognized originally Armenian.