This research was carried out to determine the seed yield and some yield components of two dwarf hybrids as compared to one standard-height sunflower hybrid ( Helianthus annuus L.) at different nitrogen rates and planting densities. The study was carried out under natural rainfed conditions at the Thrace Agricultural Research Institute in Edirne-Turkey between 1999 and 2001. The experiments were set up in split-split plots in a randomized complete block design with three replications. The main plot treatments were three different-height sunflower hybrids, DW-1, DW-2, and Trakya-80. The sub plots were three levels of nitrogen, 0, 60, and 120 kg N/ha. The sub-sub plots were three planting densities, 10 × 70 (142,850 plants/ha), 15 × 70 (95,230 plants/ ha), and 20 × 70 cm (71,430 plants/ha). Based on marginal economic analyses, the economically optimal seed yield per hectare was obtained at 50 kg N/ ha for DW-1 and at 80 kg N/ha for DW-2 and Trakya-80. In all three hybrids, increasing plant densities decreased 1000-seed weight, hull percentage, and head diameter but increased test weight in natural rainfed conditions. The highest seed yield in both dwarf hybrids was obtained with the spacing of 15 × 70 cm (95,230 plants/ha). The results of this research show that nitrogen and plant density have significant effects on seed yield and some yield components of different-height sunflower hybrids.