In this paper,the tribological properties of cuttlebone (CB)-reinforced high density polyethylene (HDPE) and Red Coral (RC)-reinforced HDPE composites were investigated.The composite specimens were prepared with a hot compression molding machine using different weight proportions of fillers blended with HDPE.The tribological behavior of the composite disks was studied using pin-on-disk tribometer under dry condition against stainless steel M30NW pins.The coefficient of friction as well as wear rate were examined to study the effects of the two fillers on the tribological performance of both composites.After wear tests,different composites were examined using a Scanning Electron Microscope (SEM).It was found that the use of cuttlebone (CB) and Red Coral (RC) as reinforcement improved the tribological properties of HDPE.