The purpose of this study was to investigate how mothers of children with developmental difficulties think about relationship between grandparents and children or mothers. In previous researches, it was clear that mothers feel negative about relationship with grandparents, but also that grandparents have some important role to support their daughter(mothers). The relationship between mothers and grandparents in daily life have much influence on their interactive communication about child's development however, thee influence differ substantially between individuals. The results indicate that mothers conceive their quality and quantity of communication with grandparents from the viewpoint of 1)support from grandparents 2)relationship between grandparents and children 3)consideration about grandparent's feeling and thoughts 4)getting involved with grandparents. However, some mothers felt difficulties about getting involved with grandparents, or about letting grandperents understand their children's developmental weakness.