Rotavirus genomic RNAs, derived from a series of human isolates that exhibit variability in the pattern of migration of the double-stranded RNA on polyacrylamide gels, were transferred to diazobenzyloxymethyl paper, and their sequence diversity was investigated. Hybridization of cDNA probes prepared from the 11 segments of rotavirus RNA indicated that considerable sequence diversity exists among these viruses. Under conditions of both low and high stringency, hybridization analysis of virus collected between 1975 and 1980 suggested that the variation among rotavirus strains may have occurred by a process involving both "drift" and "shift" in the sequence of the rotavirus genomic segments.