We describe the evolution of coastal retrogressive thaw slumps (RTSs) between 1952 and 2011 along the Yukon Coast, Canada, and provide estimates of the contribution of RTSs to the nearshore organic carbon (OC) budget. We 1) monitor the evolution of RTSs during the periods 1952-1972 and 1972-2011; 2) calculate the volume of material eroded and stocks of OC mobilized through slumping and 3) measure the OC fluxes mobilized through slumping between 1972 and 2011. Our results show a 73% increase in the number of RTSs between 1952 and 2011. RTSs displaced at least 8600*103 m3 of material. Slumping mobilized 81900*103 kg of SOC and 156*103 kg of DOC. Since 1972, 17% of the RTSs have displaced 8.6*103 m3/yr of material, with an average OC flux of 82.5*103 kg/yr. This flux represents 0.3% of the OC flux released from coastal retreat; however RTSs have a strong impact on the transformation of OC in the coastal fringe.