Rabbit reticulocyte membrane-bound ribosomes liberated by deoxycholate treatment contain degraded forms of ribosomal and messenger RNA. This degradation occurs after the liberation of the ribosomes from the membranes by the detergent because intact birosomal and messenger RNA can be extracted from washed membranes by phenol treatment. Increasing the ionic strength of the detergent buffer prevents this RNA degradation and allows the recovery of membrane-bound ribosomes capable of protein synthesis. Comparison of the proteins synthesized in vitro by the polyribosomes shows that the main protein produced by both free and membrane-bound ribosomes is globin. However, the two types of polyribosomes could be distinguished by the nonglobin proteins they produce.