The article investigates the variation of demonstrative pronouns tъ, ta, to and i, ja, je in the function of the 3rd-person pronoun in the Russian translation of the Euchologion of the Great Church (late 14th cent.). The basic pronoun in most cases is tъ, ta, to, and this usage reflects the literary norm of the Tŭrnovo school, which preserved the Old Slavonic ternary system of demonstrative pronouns. The substitutive pronoun i, ja, je, which was common in Old Russian, is used less often. In some cases, there is a formal distribution of tъ- and i- pronouns in different cases and numbers.