The scrapped tires can be utilized as an organic filler for the plastics. This study is compare to the effect of an organic and an inorganic filler on the mechanical properties of the filled plastics. Quartz was used as an inorganic filler and the rubber powder from the waste tires was used as an organic filler in this experiment. Sometimes, the surface treatment of the filler has been important for the good mechanical properties for the filled plastics. Therefore, we investigated the coating effect on the mechanical properties of the filled high density polyethylene. This study also covered the effect of the combination of the organic and the inorganic filler on the mechanical properties of the plastics.