Disclosed are a preparation method for drawn fibers that enables the preparation of drawn poly(ethyleneterephthalate) fibers exhibiting with high fineness of at least 2,000 denier while having high tenacity and excellent dimensional stability and causes almost no deterioration of tenacity during the manufacturing process of tires such as vulcanization, and a drawn poly(ethyleneterephthalate) fiber and a tire cord that are obtained by the preparation method. The preparation method for drawn poly(ethyleneterephthalate) fiber includes: melt-spinning a polymer comprising at least 90 mol % of poly(ethyleneterephthalate) having a content of terminal carboxyl group (—COOH) in the range of 20 to 30 eq/106g at a spinning speed of 2,500 to 4,000 m/min to form a undrawn fiber having a fineness of at least 2,000 denier; and drawing the undrawn fiber at a draw ratio of 1.4 to 2.4.