The growth, tissue water content, and chlorophyll, quaternary ammonium compound (QAC), choline, glycinebetaine, proline, and inorganic ion (K+. Na+, Cl−;) contents and osmotic pressure' of shoot tissue of Spinacea oleracea have been measured over a range of salinities. No succulence responses were observed at low salinities, and a decrease in fresh weight was found with increasing salinity: growth ceasing above 300 mM NaCl. Tissue K+ content was maintained at about 200 mM throughout the experimental range, but tissue Na+ and Cl− increased approximately linearly up to a salinity of 300 mM NaCl. Relatively high concentrations of glycinebetaine were found in the shoot at low salinity and a small induction was observed at 50 mM NaCl which had no significant effect on fresh weight yield. The shoot glycinebetaine content was closely correlated with sap osmotic pressure. The rates of glycinebetaine and proline accumulation were further investigated under different applied stress regimes in order to obtain basic physiological data prior to biochemical examination of the control of the biosynthetic pathways.