Linguistic characteristics of the fragmented Sogdian inscription found in Kultobe (Southern Kazakhstan) show that this inscription is the oldest of the known Sogdian texts. Many letters in it are clearly Sogdian, not Aramaic or ideographic signs: g (γ), y, p, ṣ (= č), š. At the same time, some letters, such as s or h, are different from the same letters in other Sogdian texts, including the 4th century “Ancient Letters”. Some of the orthographic peculiarities of the inscription from Kultobe are archaic too: the phoneme |ϑ| is rendered by t (taw) as in Aramaic, not by δ (dalet) as in the rest of Sogdian texts. The date of the inscription cannot yet be determined.