Electron microscopy revealed multi-layered membranes within the cytoplasmic inclusion (accumulation of nucleocapsids) produced by rabies virus. When infected BHK cells were maintained at 31 C, an enhancement in production of these membranes occurred in approximately 60% of inclusion-containing cells. Multi-layered membranes were composed of an alternate array of two different layers; an electron-dense, thin membrane and a less dense layer which was thicker. SDS-polyacrylamide gel electrophoresis and immune electron microscopy of isolated multi-layered membrane preparations demonstrated that the structures contained viral G and M2 polypeptides. Our observations suggest that these membranous structures are not a degenerative product of rabies virus infection but rather are related to the replication of viral envelope constituents, although they represent themselves to be an abortive form of viral assembly.