A hydroponic study was conducted to investigate the role of sulphur application on K/Na selectivity by sunflower and alleviation effect of sulphur on plant growth under saline conditions. Three salinity levels (0, 75, and 150 mM sodium chloride) and two sulphur levels (1 and 4 mM magnesium sulphate) were maintained in the root medium. The treatments were replicated thrice and arranged on growth chamber bench according to a complete randomized design (CRD). Seeds of Helianthus annuus (cv. Hysun-33) were germinated in quartz sand under standard conditions. One-week old seedlings were trans ferred to pots containing 2.5 l continuously aerated half strength modified Hoagland's nutrient solution. The plants were provided optimum growth conditions. First harvest on 25th and second harvest on 30th day were taken after germination. Plants grown with 4 mM sulphur level showed significant growth whereas interaction between sulphur and salinity was highly significant (P<0.01) for growth parameters like fresh weight, dry matter yield of shoot and root, diameter and length of stem and root. The positive correlation of dry matter yield with sulfur (r=0.93), potassium (r=0.99) and calcium (r=0.83) were observed, whereas sodium had negative relationship (r=-0.99) with dry matter yield. Potassium/sodium selectivity in plants was significantly higher (P< 0.01) at 4 mM sulphur level than at 1 mM.