Radiocarbon-dated paleobotanical and palynological samples record complex changes of vegetation and climate in northeastern Russia during the Late Pleistocene and Holocene. Since the Kargin Interval (middle Wisconsin equivalent), which started 50 ka ago, we can distinguish two periods that were colder than the present. The Kirgilyakh was the earliest Karginsk cool period, dating to 45–39 ka bp. The second significant cool period dates to 33–30 ka bp. The boundary between the Kargin Interval and the last Late Pleistocene glaciation (Sartan, late Wisconsin equivalent) dates from 27 ka bp. The sharp change from herbaceous mossy tundra (Sartan) to light-coniferous larch forests (Holocene) in northeastern Russia dates to 12.5 ka ago. The Holocene thermal maximum, linked to the expansion of woody plants into the modern barren-ground tundra, dates from 9.5–8 ka bp.