Comparative nucleotide and deduced amino acid sequence analyses of the RNA and proteins of several fixed rabies virus strains have allowed detailed characterization of structural-functional relations of individual virus components. Several unique features of rabies viruses have been deduced from the complete nucleotide sequences of four of the five genes and the four intergenic regions of the genome. The most extensively analyzed rabies virus gene has been that of the surface glycoprotein. Direct comparisons between the deduced amino acid sequences of glycoprotein variants have led to the location of specific sites on the glycoprotein that bind virus-neutralizing antibodies and to the identification of an epitope correlating with viral pathogenicity. Structural requirements for immunogenic activity within the glycoprotein have also been investigated. This article presents an overview of the molecular biology of rabies viruses and describes the current state of knowledge of immunobiologic characteristics of different rabies virus components.