Sunflower (Helianthus annuus L.) is one of the most widely cultivated oilseeds in the world and ranks third in importance as a source of vegetable oil. In our experiment, full-fat sunflower seed (FFSS) had 180 g/kg CP, 380 g/kg EE, and 143 g/kg CF. Among the various oilseeds available on the market, FFSS contains more ether extract (EE) and is available at a relatively low price. This high EE content contributes to a high ME per unit or high energy density of feed. The increased production and availability of hybrid FFSS coupled with its oil content make FFSS a potentially desirable ingredient in poultry feeds. In the last few years, unextracted whole seed has been used as a feed ingredient in poultry diets. This experiment was conducted to determine the apparent metabolizable energy (AMEn) of FFSS in broiler chickens.