Salinization of both salt-sensitive and salt-tolerant lettuce plants with increasing doses of NaCl, throughout the entire period of experiment induced significant increases in both glucose and fructose contents and significant decreases in sucrose content. In salt-tolerant Eskandrany cultivar, sucrose content was found either to increase significantly (at 3 dS/m NaCl), non-significant decrease (at 7 dS/m NaCl) or to decrease significantly (9 dS/m NaCl). Organic acid content (citric, oxalic and keto acids) showed significant increases in both salt-sensitive and salt-tolerant lettuce cultivars as compared with control. Proline and glycine amino acids content of both cultivars, salinized with increasing doses of NaCl, throughout the entire period of the experiment, showed significant increases. In all cases, the magnitude of accumulation of all metabolites determined was most pronounced in salt-tolerant lettuce cultivar. The results were discussed in relation to the mechanisms of salt tolerance in plants.