Evidence is presented suggesting the existence of a natural ribosome-membrane complex. A reconstruction system is described wherein free ribosomes form a complex which appears to involve cell fragments. The reconstructed complex is similar in stability to the inferred natural complex. The reconstructed complex is generated by lysozyme, and it is concluded that at least part of the inferred natural complex is also generated by lysozyme. These results are discussed with reference to existing data concerning certain membrane-associated systems in bacteria.