Abstract Microsomal membranes were isolated from the rapid growing part of hypocotyls of Phaseolus vulgaris var. Saxa. The type of ribosome—membrane interaction was determined using EDTA, puromycin and ribonuclease. EDTA treatment (3–5 mM) effected the preferential release of the small over the large ribosomal subunits from the membranes. Incubation of microsomes in puromycin at low and high KCl concentration revealed that ribosomes are attached to the membranes by the growing peptide chain and/or electrostatic linkage. Mild ribonuclease digestion released only about 10% of the membrane-bound ribosomes. Ribosome—membrane interaction in the hypocotyl of Phaseolus vulgaris resembles more that found in rat liver cells than that in cultured cells.