The objects of research were forest hydromor-phic ecosystems in the lower current of the river Sym (Krasnoyarsk Region). The research objective was to reveal prevailing types of mire phytocoenoses, to analyse the peat deposit stratig-raphy, to provide the classification scheme of types of peat. The analysis and processing of the select-ed samples of peat were carried out by the stand-ard techniques. It was established that on studied bogs four types of vegetable communities were most widespread. Wood, grassy small shrub and moss and lichen circles of vegetation, complete-ness, specific structure and degree of a protective covering were characterized. The genesis of bogs and typological variety of types of deposits were influenced by the relief, soil forming rocks and wa-ter and mineral food. It was also stated that bogs had mainly not large area and a small thickness of a peat deposit, somehow 1.5-2.0 m. According to the principles of classification 24 types of peat had been determined: from them 10 sphagnum types, 9 transitional and 5 low-mire peats. It was established that according to the frequency of occurrence and the role in addition of deposits the main types of peat were fuscum, medium, medium peat, complex peat. Other types of peat were met much less of- ten. It was pointed that the confinement of peat types was related to certain depths of stratigraphic column. The minimum and maximum exponents of decomposition and ash-content of types of peat, and also their natural humidity were given. The re-vealed tendency of increase in extent of decompo-sition and ash-content of peat in the studied bogs in comparison with similar peat of Western Siberia was explained by diluvial mineralization of peat de-posits.