Seeds of Capsicum annuum were grown hydroponically in a nutrient medium with or without NaCl and with supplemented $Ca^{2+}$. Plasma membranes were isolated from roots using a two-phase aqueous polymer technique. The lipid composition (fatty acids, phospholipids and sterols) of the purified plasma membrane was determined. In the presence of NaCl, changes in lipid composition were shown, driving the membrane to a more rigid state. This was accomplished by an increase of (i) the saturation of fatty acids, (ii) the content of stearic acid versus palmitic acid, and (iii) the sterols concentration in the membrane. The changes in the phospholipid composition were also related to NaCl, which reverted when $Ca^{2+}$ was also present in the nutrient solution. Furthermore, the alterations of plasma membrane lipid composition under salinity and calcium can be related to water transport properties of the membrane, but other physiological responses have to be taken into account.