The study about sedimentary organic carbon content in Lake Sentani Papua is very important because it has en effects in the carbon content in waters. The carbon in sediment is one of the macro nutrients for organism. Carbon, Nitrogen and Phospor has an important role in the formation of biomass. This research using survey method in sediment sampling purposively. Sampling site consists of the location of the inlet, floating net cages, the middle of the lake and outlet. The results are sedimentary organic carbon concentration in Lake Sentani respectively was at the net cages location of 22,437 mg/kg, followed by the inlet about 20,81 mg/kg, in the outlet area is about 18,3 mg/kg and in the middle area of the lake is about 1,99 mg/kg.