The paper presents the results of studies on the content and accumulation of natural and anthropogenic radionuclides in the American arborvitae (T. occidentalis L.), growing in environmentally different areas in Yoshkar-Ola. It is noted that the various organs of this type (needles, stems, roots), are characterized by unequal content of the studied radioelements. Plants growing in environmentally unfriendly areas of the city, are higher in natural radionuclides.