A field experiment was conducted during winter (rabi) seasons of 2003 to 05 at Varanasi to find out the response of Indian mustard (Brassica juncia L. Czernj and Cosson) to four levels of nitrogen (0, 40, 60 and 80 kg N/ha) and four levels of sulphur (0, 15, 30 and 45 kg S/ha) under rainfed conditions. Application of 80 kg N/ha significantly improved seed yield (1.17 and 1.28 tonnes/ha), stover yield, nitrogen uptake (54.26 and 57.52 kg/ha), protein content and oil content, probably due to better crop growth and yield attributes of Indian mustard. Among the sulphur level, 45 kg S/lia being at par with 30 kg S/ha gave significantly higher seed yield (1.18 and 1.26 tonnes/ha) stover yield, sulphur uptake (20.07 and 21.27 kg/ha) and oil and protein content. Agronomic efficiency and apparent recovery was maximum at 60 kg N/ha and 15 kg S/ha, and it declined with further increases in the levels of nitrogen and sulphur. Optimum economic dose of nitrogen was 39.5 - 46.3 kg/ha and 24.5 kg S/ha. Maximum net returns and benefit : cost ratio were observed with the application of 80 kg N and 45 kg S/ha, respectively.