The article gains an insight into the problem of modality as a complex phenomenon embracing five separate heterogeneous modal zones and their morphological, lexical and syntactical means of expression. The morphological level is presented with a number of moods which were analysed from the paradigmatic and syntagmatic view point. The category of mood in Nganasan is based on the opposition the indicative mood versus the moods of the non-indicative sphere: imperative, conjunctive, interrogative, renarrative, inferential, acceptive and others. The study of semantics of each mood revealed interlacement of various modal meanings with one another. The lexical means of expression of modality include modal verbs, modal words, modal particles and interjections. Among syntactical means special syntactical constructions, nominative sentences, inverted word order and direct address occurred. It was found that lexical and syntactical means can express different types of modality. The article also discusses to the possibilities of combining the above-considered means of expressing of modality.