The status of the environment in the development area of oil and gas condensate fields (OGCFs) in the north of Western Siberia (the Yamalo-Nenets autonomous okrug (YNAO)) has been evaluated on the basis of long-term investigations (1993–2016). The content of oil hydrocarbons, polycyclic aromatic hydrocarbons, and heavy metals (Cu, Zn, Fe, Pb, Cd, Ni, Co, Cr, Ba, Cd, and Mn) is determined in soils, natural waters, bottom sediments, and indicator plants (Larix sibirica, Betula nana, Salix lanata, Ledum decumbens, Vaccinium vitis-idaea, Vaccinium uliginosum, and Cladonia alpestris). Species pleiads, corresponding to the ecological conditions of habitats and the intensity of technogenic impact, are specified with the use of the coefficients of interspecies conjugation of plants. A complex of indicators of the transformation of natural complexes under the effect of oil and gas extraction is proposed.