The composition of organic matter (TOC, δ13C) in lacustrine sediments is an approach for reconstructions of lake environments and climate fluctuations. In lacustrine sediments, organic matter is comprised of detritus which arises from terrestrial and aquatic vascular plants and algae, as well as other organic producers (cladoceran, chironomids, etc.). Carbon isotopic compositions indicate changes in lake productivity and carbon recycling (Meyers and Ishiwatari, 1993, doi:10.1016/0146-6380(93)90100-P). Core BN2016-1 from lake Bayan Nuur was studied for stable carbon isotopes and total organic carbon (TOC) content in bulk sediments. Were measured TOC (39 sediment samples) and δ13C (42 samples) from the BN2016-1 core. The sediment samples were leached by 0.5 N HCl to remove inorganic carbon, then washed with distilled water and freeze-dried. The TOC and δ13C were measured using the (IRMS) Delta V Advantage with EA 2000 HT.