Field data on Quaternary sediments of several outcrops at Gydan Peninsula and Beliy Island and their comparison with literature data have shown that the relative sea-level changes in the southeastern part of the Kara Sea since MIS 3 differ from the average sea-level changes in the World Ocean. MIS 3 (Kargin time) marine sediments lie at elevations of up to 2-2,5 m a.s.l. at Beliy Island, Sibiryakov Island and some other Arctic islands; they are covered by the Holocene marine sand with allochtonous peat aged about 8 kA (radiocarbon). At Yavay Peninsula, marine silts and sands lie at the bottom of the coastal cliff and are overlaid by peat aged from 24 500±220 (LU-7972) to 30 710±420 (LU-7971) radiocarbon years. Above them, Holocene lacustrine sandy loam with peat and wood with ages of about 8 kA outcrop, implying that sea-level did not rise above its present position since MIS 3. In the southern part of Mammoth Peninsula, sea-level did not rise above present at least since MIS 5 (Kazantsevo time). MIS 3 deposits are continental silts with mammoth fauna, covered by the Holocene alluvium and lacustrine sediments. The range of RSL change scenarios evidences the general uplift of the Earth's crust at Gydan Peninsula and the south-eastern part of the Kara Sea since MIS 3, accompanied by differential block movements.