Litter-fall in mangrove forest is one of the very important role in carbon sequestration and carbon magnitude in the atmosphere. This research was carried out for is one year to investigate litter-fall dynamics in various sites in Mahakam Delta natural mangrove forest. The selected sites were in Tunu, Sellete and Bayur using purposive sampling method. In each site 8 trees were selected for litter trap collection and 20 trees for diameter increment measurement. Result showed that the largest biomass was found in Tunu with 25.82 ton/ha, the biggest increment was found in Selette of 1.07 ton/ha/year, and highest litter-fall was in Tunu of 14,02 ton/ha/year. In average of those three locations can absorbed 7.50 (ton C/ha), with 0.42 (ton C/ha/year), and the litter-fall increment of 5.53 (ton C/ha/year).