This study followed the effect of salicylic acid on growth criteria, photosynthetic pigments, photosynthesis, respiration, proline and the activities of some antioxidant enzymes of stressed Scenedesmus obliquus cultured for 7 days. The growth criteria (cell number and dry weight) and total pigments ofnon- stressed  and stressed  Scenedesmus obliquus cultures were significantly increased, when the algal cultures were subjected to 200 mM NaCl and treated with 100and 200 ppm of salicylic acid.  Also, Photosynthesis (oxygen evolution), respiration (dark oxygen uptake), proline, amino acids and catalase enzyme of non- salinized  and salinized Scenedesmus obliquus cultured were significantly increased, when the algal cultures were subjected to 200 mM NaCl  and treated with 100and 200 ppm of salicylic acid. However, both respiration (oxygen uptake) , lipid peroxidation as termed (malondialdhyde) and peroxidase were significantly decreased, when the algal cultures were subjected to 200 mM NaCl and treated with 400 ppm of salicylic. These values were compared with that of the control cultures.