The influence of fires on the development and chemical composition of two Rheic Hemic Histosols in the native territory of the middle taiga of the Komi Republic was estimated. The development of peat on site I (SI) located in the south boarder of the middle taiga began in the Boreal period (about nine ths. years ago¹⁴C yr BP). The growth of peat on site II (SII) located at the foothills of the Northern Urals started in the middle of the Atlantic Holocene period (about 6.7 ths. years ago¹⁴C yr BP). This work shows that during the time of development, peatlands experienced various pyrogenic events. The organic horizons were burned out and often led to a change in the dominant ground cover plants. Also, the charcoal particles formed during the fire at the forest surrounding the bogs were transported by air and accumulated in the peat. The pyrogenic history of the studied peats is different, the SI was subjected to intense fires at least twice: at the beginning of formation and in the modern period (140 years ago). The Histosol on SII experienced only low-intensity and indirect fire effect. The highest burning activity of nearest forests in both sites estimated based on charcoal content occurred at the end of the Atlantic, middle of the Subboreal periods. It was shown that an increase in the aromatic compounds occurs in horizons with pyrogenic features; in some cases, an increase in the concentration of polycyclic aromatic hydrocarbons (PAHs) was revealed. The aromatic compounds content in the SOM is determined by the content of macroscopic charcoal particles with significant correlation (C_Ar-H(C), R = 0.49, p < 0.05, C_Ar-O,N, R = 0.68, p < 0.05). It is shown that a high frequency of fires leads to an increase in carbon stocks at Histosols.