Electron microscopy revealed that the entry of Rice dwarf virus (RDV) into insect vector cells involved endocytosis via coated pits. The treatment of cells with drugs that block receptor-mediated or clathrin-mediated endocytosis significantly reduced RDV infectivity. However, the drug that blocks caveola-mediated endocytosis had a negligible effect on such infection. Infection was also inhibited when cells had been pretreated with bafilomycin A1, which interferes with acidification of endosomes. Moreover, immunofluorescence staining indicated that the virus is internalized into early endosomes. Together, our data indicate that RDV enters insect vector cells through receptor-mediated, clathrin-dependent endocytosis and is sequestered in early endosomes.