Pig rotavirus was purified from feces. The RNA from this virus was resistant to pancreatic RNase, indicating that it is double-stranded. When electrophoresed on polyacrylamide-agarose gels, pig rotavirus RNA migrated as 9 bands comprised of 11 or 12 RNA segments with a total MW of .apprx. 11 .times. 106. Co-electrophoresis experiments revelaed that the RNAs from the pig virus and 2 isolates of the calf rotavirus were indistinguishable.