The morphology and deformation behavior of the clustered, scattered and isolated hydrides in recrystallized Zr 4 have been studied by in situ SEM. It is shown that the hydride can deform plastically together with the matrix at room temperature. The deformation behavior of hydrides depends on their morphology. The clustered hydrides fracture at relatively low strain levels while the sparse hydrides are more ductile and usually fracture at a quite large strain. The isolated hydride has the best deformation capability and is difficult to fracture.