In the interwar period, Belarusan morphology, as orthography, underwent dynamic change. Many scholars (e.g., U. Dobouka, V. Vol'ski, A. Losik, Ja. Stankevich) encouraged the use of dialectal material from the West-Central dialects, since they were the carriers of the main phonological features of the developing standard Belarusan language (strong akanne and jakanne, dzekanne, cekanne and hard r). Neologisms were welcomed as long as they conformed to the phonological system of the developing standard Belarusan language (e.g., preserving akanne, in particular), but Russisms and Polonisms were to be avoided. The Belarusan press was in full bloom and printed articles, stories, poems, tales, and letters in many variants of Belarusan. This provided an opportunity for all variants of Belarusan to share in the formation of standard Belarusan. This situation also explains the mixture of morphological variations found in the interwar Belarusan press; for example, the 2nd conj. 3rd sg. en gavora and en gavoryc', or 1st conj. 3rd sg. en idze and idzec', were used interchangeably. Nouns, adjectives, pronouns, and numerals exhibited similar variants.Using examples from the interwar Belarusan press in Vilnia, Miensk, and Horadnia, in this paper I examine three features of the conjugational system of the developing standard Belarusan language, as well as the changes those features underwent during the interwar period: 1) the first and second conjugation third person singular and plural present tense verb endings (e.g., 1920s-1930s 2nd conj. eH ras—pa, 1st conj. carHŽr~b>modern: eH ras—pb~b, carHŽ; 1920s1930s flHb! FaBîpyQb, CaLHyQb>mOdern: flHb! FaBîpa4b, flHb~ carHypb); 2) the second conjugation second person plural present tense ending e [jo] (1920s1930s Bbõ Cfl~Si~e>mOdern: Bb! cfl~’pe); and 3) the second person plural imperative of the first conjugation verbs (e.g., 1920s1930s i,~sŽLÁe i cKa~b~e>modern: i,~’pe i cKa;Kb~[~e). In addition, I compare the morphological characteristics of the developing standard Belarusan language of the 1920s and 1930s to their counterparts in the presentday standard Belarusan language, with reference to the Polish and Russian equivalents. Finally, since the 1933 Belarusan language grammar reform made significant changes in the morphology of developing standard Belarusan, I make some remarks on that reform as well. My examination of the interwar Belarusan press of Vilnia, Miensk, and Horadnia shows that the morphological characteristics of the thrce language variants developed steadily during that time. There wore no drastic differences in the morphology of the three Belarusan language variants. For example, most of the third person plural verbs of the second conjugation were conjugated in the present tense according to one type of the first conjugation verbs. Those were the verbs whose stem ended in a vowel and having an ending of c' in the infinitive (e.g., nb~b, Ka~‡L~b). However, the morphological characteristics of 1920s and 1930s Belarusan significantly dominated those morphological characteristics with which they were replaced as a result of the 1933 Belarusan grammar reform. For example, the Soviet 1933 Belarusan language grammar reform eliminated the stressed second person plural e ending of these verbs. Consequently, the second person plural endings of the present tense of all fõrst conjugation verbs were to be standardised on the basis of npaqyetSe '(you) work', flb/mae~e '(you) read'; hence a~33e~e '(you) lead, ~ce~e '(you) carry' rather than ffe6~ye, nec~ye. Undoubtedly, some changes were necessary in the developing language; however, as the data on Belarusan morphology show, the Soviet 1933 Belarusan language reform also disrupted the organic development of standard Belarusan.