A field experiment was conducted during winter (rabi) season of 1990-91 and 1991-92 to study the individual and interactive effects of graded levels of S and P on 'Varuna' Indian mustard [Brassica juncea (L.) Czernj. & Cosson]. Seed yield was found significantly increased with S applications @ 60 kg/ha. With S addition @ 30, 60 and 90 kg/ha, the increases in seed yield over control were 121, 157 and 176% respectively. Similar increases in seed yield with P2O5 applications @ 30 and 60 kg/ha were 36 and 82% respectively. A significant positive interaction between the 2 nutrients in increasing seed and straw yields was observed, giving the highest seed (21.5 q/ha), and straw (69.0 q/ha) yields due to combined applications of S and P2O5 at their maximum rates (S 90, P2O5 60 kg/ha). An improvement in seed : straw ratio accompanied by early crop maturity, as evident from flower count, was affected by both the nutrients up to their application rates of 30 kg/ha individually. Highest seed : straw ratio (0.33) was evident from the treatment combinations of 60 kg SO and 60 kg P2O5/ha.