A linear gradient elution chromatography of RNA of the posterior silkgland of mature silkworm larvae was conducted on a methylated fibroin-celite column, in attempts at reviving the specific interaction in vivo between fibroin and a template RNA and also utilizing it to a unique method of isolating the protein-specific RNA. RNA was shown thereby to be well fractionated into 3 or 4 components at a low ionic strength and in a mild pH range of ca. 4.8 to 8.6, with a 100 % recovery. However, contrary to authors' reasoning, no substantial difference could have been detected in respect of the elution pattern between RNAs obtained from the normal worm and from the mutant worm incapable of synthesizing fibroin. Consequently, use of intact fibroin itself besides the methylated one was suggested as a more specific chromatographic interaction reagent. It is now under study with a partial success.