Effects of the adhesion between filler particle and matrix on the erosion rate were studied in cured epoxy resin filled with glass beads having mean diameter 17 mu m. In order to observe the effect of adhesion on erosion rate, the filler particles were treated with silane coupling agent, silicone oil and washed by acetone as well. The filler content of the specimen was varied and also the specimens were attacked by different size angular particles. The comparison of each type of specimen shows that by using acetone and silicone oil for surface treatment, the erosion rate is relatively high. Whereas the specimen in which the filler was treated by silane have low erosion rate. The difference of erosion behavior is influenced by impacting particle size and filler content. Using small impacting particles and also low filler content, the erosion behavior between silane and acetone treated was quite different. On the other hand, using large impacting particles and high filler content, the erosion behavior between them was similar.