The feeding value as roughage of whole crop silage, ammoniated and intact paddy rice straw was studied at the full-ripe stage. Plant materials used were 'Nihonbare', an early variety, and 'suigen 258', a late variety obtained by some Japanese varieties and a Korean variety. Sheep were experimental animals for the digestion trial. Quality of whole crop silage was good in both 'Nihonbare' and 'Suigen'. Crude protein digestibility of whole crop silage was significantly higher in 'Suigen' than in 'Nihonbare'. In comparison with each chemical composition of ammoniated and intact rice straw of both kinds, the content of crude protein and Ca of ammoniated rice straw was significantly higher than that of intact, while nitrogen-free extract content of intact straw was significantly higher than that of ammoniated. P content of 'Suigen' was significantly higher in intact rice straw than in ammoniated. In both kinds, the digestibility of crude protein and crude fat was significantly higher in ammoniated rice straw than in intact. In both kinds, digestible crude protein content of ammoniated rice straw was significantly higher than that of intact. In 'Nihonbare', total digestible nutrients content of intact straw was significantly lower than that of ammoniated.