The article considers models of verbal word-formation and their structural composition; special attention is paid to word-forming stems and suffixes with the help of which two types of models in the word-building system of the Moksha language have been revealed: 1) with mutational suffixes, 2) with modifying suffixes; the productivity of each model has been investigated. In addition, the suffixes are characterized from the viewpoint of vocalism, consonantism, component structure and syllables quantity; also the structure of some suffix morphemes in relation to their opposition has been dealt with.