In the present study salicylic acid (SA) treatment and challenge by Uncinula necator (Schwein.) Burr., significantly induced the systemic acquired resistance components in grapevine (Vitis vinifera L. cv. Sultana). Chitinase (CHV, EC 126.96.36.199) and beta-1,3-glucanase (Laminarinase, EC 188.8.131.52) activities increased in SA-treated (100, 200 and 400 ppm) as well as in U. necator infected plants and the highest enzymatic activity was observed in leaves treated with 100 ppm of SA. In contrast, total protein content and accumulation of endogenous free-SA in the leaves were observed at the highest rate of 200 ppm of SA-treatment. Salicylic acid also affected photosynthetic pigments by causing decrease in chlorophyll a and b contents and increase in carotenoids content. Treatment of grapevine leaves with SA provides an attractive tool for the control of powdery mildew disease in grapevine.