The paper deals with one of the components of text-to-speech synthesis of the Lithuanian language, namely – automatic text stressing. The present work substantiates the necessity to divide words into fixed and variable parts used to build different grammatical forms, as well as to store only those parts rather than the whole worlds in the dictionary. According to the inflexion method, all words of the Lithuanian language are divided into three groups (noun-adjectives, verbs and non-inflectional words) and each group is analysed separately. The type of information, as well as the form in which it is to be stored, has been established for each group and the algorithm by means of which the grammatical form of a word can be recognised and stressed, has been presented.