The replication of defects from a 4H-SiC wafer to the epitaxial layer was investigated by reflection X-ray topography and high-resolution XRD. The closed-core screw dislocations are perfectly replicated from the wafer to the epitaxial layer. Most of the basal plane dislocations are not replicated but a few are observed at the same position of epitaxial layer as that in the substrate. Their concentration is reduced when the thickness of the epitaxial layer increases.