Seventeen temperature-sensitive mutants of the Concan subtype of the New Jersey serotype of vesicular stomatitis virus have been isolated following mutagenesis and assigned to two complementation groups: CC/A, containing three mutants, and CC/B, containing 14 mutants. Prototype mutants of these two Concan groups efficiently complemented prototype mutants of the Hazelhurst complementation group (with the exception of the corresponding group) which correspond to genes specifying the L, N, M and NS proteins. The pattern of intersubtypic complementation allowed the correlation of the Concan CC/B group with the Hazelhurst B group (L gene) and of the Concan CC/A group with the Hazelhurst A group (N gene). In contrast, the Concan prototype mutants failed to complement the prototype mutant of each of the five Indiana complementation groups for which genetic assignments have been made. The partitioning of intracellular nucleocapsids of the Concan and Hazelhurst subtypes during isolation were identical, and distinct from that of Indiana serotype intracellular nucleocapsids. The M protein of the Concan, but not of the Hazelhurst, subtype was observed to migrate as a doublet on SDS-polyacrylamide gels electrophoresed in a phosphate buffer.