Field experiments were conducted for three years (1984-1936) during the summer season (Jan-Apr) at the University of Agricultural Sciences, Bangalore, India, to study the effect of moisture regimes, plant density, and fertilizer levels on grain yield of sunflower. Moisture regimes, plant density, and fertilizer levels independently influenced the seed yield. At this âgroclimatic condition prevailing during the summer season around Bengaluru, maximum seed field in sunflower can be realised by irrigating the crop at 0.6 CPE at the plant density of 55,555 plants ha-1. An increase in fertilizer levels increased the seed yield in sunflower, and maximum seed yield was realised at the higher fertilizer dose of 90:135:90 kg N: P:K ha-1. Water use efficiency in terms of seed field produced per unit amount of irrigation water applied increased with increased quantity of irrigation. An increase in plant density reduced water use efficiency. Water use efficiency increased with an increase in fertilizer levels.