1. 1. Small amounts of RNA are present in washed membrane ghosts prepared by lysis of Streptococcus fecalis (ATCC No. 9790) protoplasts. Evidence was sought for differences between the membrane ghost RNA and RNA in other cell fractions, particularly ribosomes. 2. 2. After pulse labelling intact cells with [ 32P]orthophosphate, the membrane ghost RNA was found to be the most rapidly labelled as judged by measurement of the specific radioactivity of isolated 32P-labelled 2′(3′)-mononucleotides. Insoluble, easily sedimentable fragments of membrane ghosts obtained after sonication still retained RNA also with the most heavily 32P-labelled nucleotides. The nucleotide composition of the bulk and newly synthesized [ 32P]RNA in the membrane ghosts resembled the composition of ribosome RNA and the RNA in a DNA-rich fraction, but not s-RNA. 3. 3. Electron micrographs of the membrane ghosts indicate the presence of ribosomes. They are associated with a filamentous network and they are also situated in large numbers within a hollow tubular structure. 4. 4. It is concluded that in Streptococcus fecalis a rapidly synthesized RNA is associated specifically with membranous structures probably in membrane-associated ribosomes. 5. 5. Some information on the nature and amounts of other chemical components in the membrane ghosts is presented.